MCAT Physical : MCAT Physical Sciences
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Example Questions
Example Question #251 : Mcat Physical Sciences
Two children are playing on an icy lake. Child 1 weighs 50kg, and child 2 weighs 38kg. Child 1 has a backpack that weighs 10kg, and child 2 has a backpack that weighs 5kg.
Over the course of the afternoon, they collide many times. Four collisions are described below.
Collision 1:
Child 1 starts from the top of a ramp, and after going down, reaches the lake surface while going 5m/s and subsequently slides into a stationary child 2. They remain linked together after the collision.
Collision 2:
Child 1 and child 2 are sliding in the same direction. Child 2, moving at 10m/s, slides into child 1, moving at 2m/s.
Collision 3:
The two children collide while traveling in opposite directions at 10m/s each.
Collision 4:
The two children push off from one another’s back, and begin moving in exactly opposite directions. Child 2 moves with a velocity of +8m/s.
Child 1 hooks up a jet motor to a sled, and brings it to the icy lake. She sets up her sled, and launches from a velocity of +8 m/s with an acceleration of 15m/s2. After ten seconds, how fast is she traveling? Assume the lake is frictionless.
-150m/s
-158m/s
-8m/s
158m/s
150m/s
158m/s
For this question, we have to use the translational motion equations:
Example Question #3 : Motion In One Dimension
Two children are playing on an icy lake. Child 1 weighs 50kg, and child 2 weighs 38kg. Child 1 has a backpack that weighs 10kg, and child 2 has a backpack that weighs 5kg.
Over the course of the afternoon, they collide many times. Four collisions are described below.
Collision 1:
Child 1 starts from the top of a ramp, and after going down, reaches the lake surface while going 5m/s and subsequently slides into a stationary child 2. They remain linked together after the collision.
Collision 2:
Child 1 and child 2 are sliding in the same direction. Child 2, moving at 10m/s, slides into child 1, moving at 2m/s.
Collision 3:
The two children collide while traveling in opposite directions at 10m/s each.
Collision 4:
The two children push off from one another’s back, and begin moving in exactly opposite directions. Child 2 moves with a velocity of +8m/s.
Child 1 hooks up a jet motor to a sled, and brings it to the icy lake. She sets up her sled, and launches from a velocity of 8m/s with an acceleration of 15m/s2. After fifteen seconds, how far has she traveled?
600km
1.8km
1.8m
1800km
600m
1.8km
For this question, we have to use a translational motion equation.
Example Question #21 : Translational Motion
If a ball was thrown straight up at 10m/s and strikes the ground after two seconds, what maximum height did the ball reach?
2m
5m
15m
7m
10m
5m
This question can be solved using multiple strategies. One strategy uses the equation 
vf = 0m/s
vo = 10m/s
a = -10m/s2
We use a negative acceleration because gravity is in the opposite direction of the movement of the ball. When we plug in all the values we find that d= 5m.
Another strategy uses the projectile time. In projectile motion we know that velocity is zero at the maximum height. Using only half of the projectile time, we can solve for the maximum height.
Example Question #73 : Newtonian Mechanics And Motion
If a ball is thrown straight up into the air at a velocity of 20m/s and strikes the ground five seconds later, what is the velocity of the ball at its maximum height?
10m/s
5m/s
3m/s
0m/s
7m/s
0m/s
The velocity of the ball at the maximum height is equal to zero. Since the ball was thrown stright up, both the velocity in the x direction and the y direction are equal to zero at its peak. If the ball were thrown at an angle, only the velocity in the y direction would be equal to zero. This is a good point to keep in mind when doing kinematic problems. Note that there is still acceleration acting on the ball (gravity) of 10m/s2 which brings the ball back to the ground.
Example Question #1 : Motion In One Dimension
If an object has an initial velocity of 3m/s and a constant acceleration of 2m/s2, how fast will the object be moving after five seconds?
15m/s
7m/s
13m/s
10m/s
3m/s
13m/s
Using the equation 
Example Question #11 : Motion In One Dimension
In five seconds a runner moves from the 50m mark to the 75m mark along a straight path. What is the runner's average velocity?
To find the average velocity, the displacement needs to be measured. The displacement the difference betweent eh final position and the initial position.
Using the equation for velocity, 
Example Question #11 : Motion In One Dimension
A child throws a ball straight up into the air. He throws the ball with an initial velocity of 
How long will it take for the ball to reach a velocity of 
The baseball will never have a velocity of 
In order to solve for the time at which the ball has a velocity of 
Keep in mind that 1.6s is also a time at which the velocity is 
Example Question #1 : Linear Motion And Momentum
If a 15kg ball takes five seconds to strike the ground when released from rest, at what height was the ball dropped?
125m
75m
100m
50m
250m
125m
Using the equation 
Example Question #2 : Motion In One Dimension
How far will an object travel after ten seconds if it is dropped into a bottomless pit?
50m
500m
250m
300m
25m
500m
Since the object is dropped, the inital velocity is zero. Gravity is the only acceleration, the time is ten seconds, and the distance at which the object travels is unknown.
The equation 
Example Question #3 : Motion In One Dimension
How long does it take an object to travel a distance of 30m from rest at a constant acceleration of 2m/s2?
Using the equation 
Since the object started at rest, 
Plugging in the remaining values we can find that t = 5.5s.
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