00:02
Okay, so number one, as for the time, will it take for the ball to reach its max height.
00:10
When it was thrown at the planet with an accession to grab the 5 meter per cent square.
00:16
So the one for this will use the kinematic equation for its thin velocity by vertical component because it relates the velocity, it not has final velocity, with the acceleration and the time.
00:31
And for an object that is moving under gravity at max height, its final velocity is zero.
00:42
So this is the equation.
00:47
At max height, v.
00:53
Ys equals to zero.
00:58
And for motion under gravity, such as this one, the vertical component of acceleration is negative to acquisition to be gravity.
01:10
Then our equation because of this.
01:15
And i select in p to the life size, since this is what we need, then we have this.
01:19
And so then we're given an initial velocity of 45 meter per second.
01:23
In g, 5 meter per second, square, you can find a t equals to 9 seconds.
01:30
For number two, it asks for the acceleration.
01:36
So we will use the second block of motion, equation for that, to determine the acceleration since it illustrates the net force, with the mass.
01:48
We are given the two forces of the object and net force is some of that.
01:54
So net force is the product of the mass of the object in the acceleration.
02:05
Okay, following the partition coordinate system, we have positive force for the air resistance and negative for the gravitational force.
02:27
And we know that the gravitational force is the weight, which is the product.
02:33
Of the mass of the object and its acceleration due to gravity.
02:40
When our question goes like this.
02:42
Now isolating a, the next side is this is what we move.
02:47
Then we have this.
02:52
And solving, we have 15 newtons.
02:57
We're given an air resistance.
03:05
Force of air resistance of 15 newtons.
03:08
We're given the mass of the object, rock, the accession due to gravity, assuming that this is on earth.
03:20
So that is 2.
03:22
Gravity is 920 meter per second square.
03:28
In solving, you can find that this is equals to negative 7 .606 meter per second square.
03:52
So that direction is the same as the gravity.
04:02
I mean, that's right, it's the same as the gravitational force.
04:07
Swat, which is downwards.
04:18
Next, number three, as for the magnitude of the frictional force.
04:25
Again, we will use the second off -motion, which is this.
04:32
And you know that net, of course, is some of the course is acting on the object, so we have the applied force and the functional force.
04:41
Now that we denote the frictional force as negative, since it's acting on the direction of the motion of the object.
04:46
The opposite direction...