1 a car goes around a circular curve on a horizontal road at constant speed what is the directio

Name: 1 a car goes around a circular curve on a horizontal road at constant speed what is the direction of the friction force on the car due to the roada tangent to the curve in the forward direct 57725
Uploaded: 2022-06-01T20:32:38-08:00
Duration: 7 min 4 s
Channel: Adam Moon
Description: 1 a car goes around a circular curve on a horizontal road at constant speed what is the direction of the friction force on the car due to the roada tangent to the curve in the forward direct 57725

Question

A car goes around a circular curve on a horizontal road at a constant speed. What is the direction of the friction force on the car due to the road? A) tangent to the curve in the forward direction B) tangent to the curve opposite to the direction of the car's motion C) perpendicular to the curve outward D) perpendicular to the curve inward E) There is no friction on the car because its speed is constant. 2) Two small balls, A and B, attract each other gravitationally with a force of magnitude F. If we now double both masses and the separation of the balls, what will now be the magnitude of the attractive force on each one? A) 16F B) 8F C) 4F D) F E) F/4 3) A spaceship is traveling to the Moon. At what point is it beyond the pull of Earth's gravity? A) when it gets above the atmosphere B) when it is halfway there C) when it is closer to the Moon than it is to Earth D) It is never beyond the pull of Earth's gravity. 4) A hypothetical planet has a mass of one-half that of the earth and a radius twice that of the earth. What is the acceleration due to gravity on the planet in terms of g, the acceleration due to gravity at the surface of the earth? A) g B) g/2 C) g/4 D) g/8 E) g/16 5) Two planets have the same surface gravity, but planet B has twice the mass of planet A. If planet A has a radius r, what is the radius of planet B? A) r/2 B) r C) r*2 D) 4r E) 2r 6) A 250-kg motorcycle goes around an unbanked turn of radius 13.7 m at a steady 96.5 km/h. What is the magnitude of the net force on the motorcycle? A) 719 N B) 2.95 × 103 N C) 1.31 × 104 N D) 4.31 × 104 N 7) A 2.0-kg ball is moving with a constant speed of 5.0 m/s in a horizontal circle whose diameter is 1.0 m. What is the magnitude of the net force on the ball? A) 0 N B) 20 N C) 40 N D) 50 N E) 100 N 8) A car moving at a steady 10 m/s on a level highway encounters a bump that has a circular cross-section with a radius of 30 m. The car maintains its speed over the bump. What is the normal force exerted by the seat of the car on a 60.0-kg passenger when the car is at the top of the bump? A) 200 N B) 390 N C) 790 N D) 490 N E) 590 N 9) Pulling out of a dive, the pilot of an airplane guides his plane into a vertical circle. At the bottom of the dive, the speed of the airplane is 320 m/s. What is the smallest radius allowable for the vertical circle if the pilot's apparent weight is not to exceed 7.0 times his true weight? A) 1700 m B) 1500 m C) 2200 m D) 230 m E) 42 m 10) A 20-g bead is attached to a light 120 cm-long string as shown in the figure. If the angle α is measured to be 18°, what is the speed of the mass? A) 0.55 m/s B) 2.0 m/s C) 3.8 m/s D) 1.3 m/s E) 1.1 m/s

          A car goes around a circular curve on a horizontal road at a constant speed. What is the direction of the friction force on the car due to the road?
A) tangent to the curve in the forward direction
B) tangent to the curve opposite to the direction of the car's motion
C) perpendicular to the curve outward
D) perpendicular to the curve inward
E) There is no friction on the car because its speed is constant.

2) Two small balls, A and B, attract each other gravitationally with a force of magnitude F. If we now double both masses and the separation of the balls, what will now be the magnitude of the attractive force on each one?
A) 16F
B) 8F
C) 4F
D) F
E) F/4

3) A spaceship is traveling to the Moon. At what point is it beyond the pull of Earth's gravity?
A) when it gets above the atmosphere
B) when it is halfway there
C) when it is closer to the Moon than it is to Earth
D) It is never beyond the pull of Earth's gravity.

4) A hypothetical planet has a mass of one-half that of the earth and a radius twice that of the earth. What is the acceleration due to gravity on the planet in terms of g, the acceleration due to gravity at the surface of the earth?
A) g
B) g/2
C) g/4
D) g/8
E) g/16

5) Two planets have the same surface gravity, but planet B has twice the mass of planet A. If planet A has a radius r, what is the radius of planet B?
A) r/2
B) r
C) r*2
D) 4r
E) 2r

6) A 250-kg motorcycle goes around an unbanked turn of radius 13.7 m at a steady 96.5 km/h. What is the magnitude of the net force on the motorcycle?
A) 719 N
B) 2.95 × 103 N
C) 1.31 × 104 N
D) 4.31 × 104 N

7) A 2.0-kg ball is moving with a constant speed of 5.0 m/s in a horizontal circle whose diameter is 1.0 m. What is the magnitude of the net force on the ball?
A) 0 N
B) 20 N
C) 40 N
D) 50 N
E) 100 N

8) A car moving at a steady 10 m/s on a level highway encounters a bump that has a circular cross-section with a radius of 30 m. The car maintains its speed over the bump. What is the normal force exerted by the seat of the car on a 60.0-kg passenger when the car is at the top of the bump?
A) 200 N
B) 390 N
C) 790 N
D) 490 N
E) 590 N

9) Pulling out of a dive, the pilot of an airplane guides his plane into a vertical circle. At the bottom of the dive, the speed of the airplane is 320 m/s. What is the smallest radius allowable for the vertical circle if the pilot's apparent weight is not to exceed 7.0 times his true weight?
A) 1700 m
B) 1500 m
C) 2200 m
D) 230 m
E) 42 m

10) A 20-g bead is attached to a light 120 cm-long string as shown in the figure. If the angle α is measured to be 18°, what is the speed of the mass?
A) 0.55 m/s
B) 2.0 m/s
C) 3.8 m/s
D) 1.3 m/s
E) 1.1 m/s

Added by Meghan H.

University Physics with Modern Physics

Hugh D. Young 14th Edition

Instant Answer

Solved by Expert Adam Moon

06/01/2022

Step 1

Step 1: For question 1, the direction of the friction force on the car due to the road is towards the center of the circular curve, which is perpendicular to the curve inward. Show more…

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A car goes around a circular curve on a horizontal road at a constant speed. What is the direction of the friction force on the car due to the road? A) tangent to the curve in the forward direction B) tangent to the curve opposite to the direction of the car's motion C) perpendicular to the curve outward D) perpendicular to the curve inward E) There is no friction on the car because its speed is constant. 2) Two small balls, A and B, attract each other gravitationally with a force of magnitude F. If we now double both masses and the separation of the balls, what will now be the magnitude of the attractive force on each one? A) 16F B) 8F C) 4F D) F E) F/4 3) A spaceship is traveling to the Moon. At what point is it beyond the pull of Earth's gravity? A) when it gets above the atmosphere B) when it is halfway there C) when it is closer to the Moon than it is to Earth D) It is never beyond the pull of Earth's gravity. 4) A hypothetical planet has a mass of one-half that of the earth and a radius twice that of the earth. What is the acceleration due to gravity on the planet in terms of g, the acceleration due to gravity at the surface of the earth? A) g B) g/2 C) g/4 D) g/8 E) g/16 5) Two planets have the same surface gravity, but planet B has twice the mass of planet A. If planet A has a radius r, what is the radius of planet B? A) r/2 B) r C) r*2 D) 4r E) 2r 6) A 250-kg motorcycle goes around an unbanked turn of radius 13.7 m at a steady 96.5 km/h. What is the magnitude of the net force on the motorcycle? A) 719 N B) 2.95 × 103 N C) 1.31 × 104 N D) 4.31 × 104 N 7) A 2.0-kg ball is moving with a constant speed of 5.0 m/s in a horizontal circle whose diameter is 1.0 m. What is the magnitude of the net force on the ball? A) 0 N B) 20 N C) 40 N D) 50 N E) 100 N 8) A car moving at a steady 10 m/s on a level highway encounters a bump that has a circular cross-section with a radius of 30 m. The car maintains its speed over the bump. What is the normal force exerted by the seat of the car on a 60.0-kg passenger when the car is at the top of the bump? A) 200 N B) 390 N C) 790 N D) 490 N E) 590 N 9) Pulling out of a dive, the pilot of an airplane guides his plane into a vertical circle. At the bottom of the dive, the speed of the airplane is 320 m/s. What is the smallest radius allowable for the vertical circle if the pilot's apparent weight is not to exceed 7.0 times his true weight? A) 1700 m B) 1500 m C) 2200 m D) 230 m E) 42 m 10) A 20-g bead is attached to a light 120 cm-long string as shown in the figure. If the angle α is measured to be 18°, what is the speed of the mass? A) 0.55 m/s B) 2.0 m/s C) 3.8 m/s D) 1.3 m/s E) 1.1 m/s

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Transcript

00:03 All right, so you had some multiple choice questions here about primarily centripetal force and gravitational attraction.

00:13 So i did some of them for you.

00:17 I can't do all 10 in one fail swoop because i run out of space on the video.

00:26 So i'm just going to talk about these first six and the concepts.

00:30 And that should help you with the other ones.

00:35 So number one is about circular motion.

00:39 If i have an object that's going around in a circle, the net force is the centripetal force.

00:47 And that centrifugal force is always pointed directly to the center of the circle.

00:52 So what is the centripetal force in scenario one? it's the friction on the tires with the surface of the road.

01:02 That's what's maintaining the circle.

01:04 Without that, it doesn't stay in the circle and flies off off to the side of the road.

01:11 So friction maintains a circular motion, and therefore it must be directed towards the center.

01:18 So the force of friction is directed towards the center.

01:21 So you can figure that out from there.

01:23 So if i have a curve of a track, it's got to be towards the center.

01:28 Now i'll help you lift the answer to number one.

01:32 Number two is all about the ratio of how the law of motion, or law of gravitation works.

01:41 So the law of gravitation is the weight of an object is equal to capital g, m1, times m2, divided by r squared.

01:52 R is the distance from the center of the planet.

01:57 So if they have the same gravity to start with, and we multiply the masses, double their masses, not that they have the same gravity, but they have some gravitational force.

02:10 If i'm going to double both of their masses, it's two times two.

02:15 The change is going to be in a magnitude of four in the numerator.

02:20 Well, if i also double the distance between the two, i'm going to change the magnitude and the denominator by two squared, which is also four.

02:31 So the magnitude of change is four divided by four, which is one.

02:36 So there is no change.

02:38 And so they will have the same gravitational attraction as before.

02:46 So number three, one thing about earth's gravity is that it gets smaller and smaller, the farther away you are from it.

02:55 That goes for any object in space.

02:58 But it never goes away completely.

03:00 It becomes less significant as you get closer to the moon, but it's not disappearing.

03:06 It's still there.

03:07 So earth gravity may diminish, but it is still there.