(II) Can cars "stop on a dime"? Calculate the acceleration of a 1400-kg car if it can stop from 35 km/h on a dime (diameter $=$ 1.7 cm). How many $g$'s is this? What is the force felt by the 68-kg occupant of the car?

Answer

a. $-2800 \mathrm{m} / \mathrm{s}^{2}$
b. $280 g^{\prime} s$
c. $1.9 \times 10^{5} \mathrm{N}$

July 23, 2020

how did you get 1.9x10^5?

Michael C.

September 23, 2020

The video has an error for part c. You wrote the car's mass, not the person's mass. It should be 68kg*-2779.

Top Physics 101 Mechanics Educators

Christina K.

Rutgers, The State University of New Jersey

Watch More Solved Questions in Chapter 4

Problem 1

Problem 3

Problem 4

Problem 5

Problem 6

Problem 7

Problem 8

Problem 9

Problem 10

Problem 11

Problem 12

Problem 13

Problem 14

Problem 15

Problem 16

Problem 17

Problem 18

Problem 19

Video Transcript

Alright, can car stop on a dime? Obviously the answer is no, um, we're gonna have a 14,000 kg car That's traveling at 35 km per hour to stop on a dime. Which distance is 1.7 cm? How many GS is this? Well, I'm going to convert this into meters, so there's 1000 m in a kilometer And then there's a 3600 seconds in an hour hour hour. Okay, so that's going to be meters per second. Now, this also, I'm going to rewrite it as meters. Okay, B squared equals V initial squared plus two A time's D. So, uh, the final velocity is going to be zero. So the initial squared is two A D. And so A is going to be V zero squared over too deep. So let's see here, I'm going to write V equals and then I'm going to put in what I know about V 35 times 1000 Divided by 3600. So that would be 9.72 m/s. So V whoops. The acceleration is V squared over two D. Whoops. Yeah, Over to D. So that would be that. Now we want to know how many Gs that is. That would be A over 9.81. That would be 280 jesus. Okay, what's the force will force is mass times acceleration? So the mass would be a 68 kg occupant and the acceleration would just be a so that would be 189 kill. Oh, Newton's of force. Thank you for watching.

Get More Help with this Textbook