MCAT Physical : MCAT Physical Sciences
Study concepts, example questions & explanations for MCAT Physical
All MCAT Physical Resources
Example Questions
Example Question #2 : Newton's Second Law
What is the acceleration due to gravity on a planet on which an object with a mass of 20.0kg has a weight of 270N?
13.5m/s2
27m/s2
0.074m/s2
10m/s 2
13.5m/s2
Solve the following equation for acceleration, using the values given in the question.
Example Question #61 : Forces
A 2kg lead ball is loaded into a spring cannon and the cannon is set at a 45º angle on a platform. The spring has a spring constant of 100N/m and the ball and spring system is compressed by 1m before launch. While the ball is in flight air resistance can be neglected, and the ball finishes its flight by landing at a cushion placed some distance away from the cannon.
When the ball leaves the cannon, how fast is it traveling?
5m/s
10m/s
20m/s
9m/s
10m/s
Think back to the 3 main kinematics equations that we know:
vf2 = vi2 + 2aΔx
vf = vi + at
Δx = vit + ½at2
Newton’s second law can be used in combination with the spring force equation to solve for the acceleration of the system. Remember that any force, whether it is kinematic, electrical, or gravitational, is equal to Newton’s second law.
Fspring = kx = masystem
Now we need to choose which equation gives us the final velocity, given that we know the acceleration and the change in position (1m).
vf2 = vi2 + 2aΔx
vf2 = (0 m/s)2 + 2(50 m/s2)(1 m) = 100 m2/s2
Example Question #1 : Understanding Accelerations
A car moving at 40m/s suddenly applies a braking force and comes to rest in 20s, with constant deceleration. If the car has a mass of 2000kg, what is the braking force?
40000N
–4000N
4000N
–2000N
–8000N
–4000N
First we can calculate the acceleration.
Using F = ma with the magnitude of the acceleration we can find the force.
Example Question #3 : Newton's Second Law
A 2000kg car with a velocity of 
The truck experiences the greater force and the car experiences the greater acceleration
The car and the truck experience equal force and the car experiences greater acceleration
The truck experiences the greater force and the greater acceleration
Both the car and the truck experience equal force and acceleration
The car experiences the greater force and the greater acceleration
The car and the truck experience equal force and the car experiences greater acceleration
The car and the truck experience equal and opposite forces, but since the car has a smaller mass it will experience greater acceleration than the truck according to the equation F = ma.
A greater mass will decrease the acceleration.
Example Question #421 : Mcat Physical Sciences
A force of 
The block moves with a constant velocity
For this question we must use Newton's second law. We have to use the formula 
Example Question #11 : Newton's Second Law
A 
For this question we must use Newton's second law. We have to use the formula 
Example Question #1 : Other Forces
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.
Regarding the force of gravity pulling child 1 down the ramp, and the force of friction acting on the two children moving after the collision __________.
the conservative nature of forces depend on the bodies being acted upon
friction is a conservative force and gravity is a nonconservative force
friction is a nonconservative force and gravity is a conservative force
both are conservative forces
both are nonconservative forces
friction is a nonconservative force and gravity is a conservative force
Conservative forces are associated with a potential energy. The gravitational force that gives rise to the potential energy of child 1 at the top of the ramp is conserved, in a sense, as she converts it to kinetic energy during her trip down to the lake surface.
Friction has no associated potential energy, and so is considered nonconservative.
Example Question #421 : Mcat Physical Sciences
Which of the following is not a conservative force?
Gravity
Electrostatic attraction
Electrostatic repulsion
Friction
Friction
Friction is a non-conservative force, meaning that the work it does depends on the path taken by the object. For example, moving a brick in a long zig-zag across the table will generate more heat from friction than moving it in a straight line across the table.
Electric and gravitational forces are conservative. This can be tested by knowing a constant equation to calculate the energy associated with these forces; such equations are applicable regardless of path. No such equation exists for frictional energy.
Example Question #422 : Mcat Physical Sciences
A 2kg lead ball is loaded into a spring cannon and the cannon is set at a 45º angle on a platform. The spring has a spring constant of 100N/m and the ball and spring system is compressed by 1m before launch. While the ball is in flight air resistance can be neglected, and the ball finishes its flight by landing at a cushion placed some distance away from the cannon.
If air resistance could not be neglected, how should the positioning of the cushion change?
Closer
Not Enough Information to Determine
Further
Same Location
Closer
Air resistance is a form of friction that acts in the direction opposite motion, slowing down an object. If the ball spends less time in flight, it will travel less of a distance, requiring the cushion to be placed closer to the launch position.
Example Question #423 : Mcat Physical Sciences
Which of the following fundamental forces is the weakest in magnitude?
Weak force
Electromagnetic force
Nuclear force
Gravitational force
Gravitational force
While one might expect the "weak" force to be the weakest of the four universal forces, the gravitational force is actually several orders of magnitude weaker than the weak force.
In order from strongest to weakest, the fundamental forces are the strong (nuclear) force, electromagnetic force, weak force, and gravitational force.
All MCAT Physical Resources
