KINEMATICS KINGDOM
Describe the motion of an object with constant negative acceleration and positive velocity
What is the object is slowing down?
A student pulls a box across a horizontal surface at constant speed. Which of the following must be true about the forces acting on the box?
A. The applied force is greater than the frictional force.
B. The applied force is equal to the frictional force.
C. There is no normal force acting on the box.
D. The net force on the box is in the direction of motion.
What is: B. The applied force is equal to the frictional force?
Why does lifting a box slowly or quickly require the same amount of work (neglecting friction)?
What is work depends on force and displacement, not the time it takes?
Why can a small object have the same momentum as a large one?
What is momentum depends on both mass and velocity — a smaller mass can compensate with a higher speed?
A rock is dropped from a height of 45 m. How long does it take to hit the ground?
What is: 3.03 seconds?
A car accelerates from rest at 3 m/s² for 5 seconds. What is its final velocity?
What is: 15 m/s?
Why does a book resting on a table experience no net force, even though gravity is acting on it?
What is the normal force from the table balances the gravitational force, resulting in zero net force?
How can an object have mechanical energy but no kinetic energy?
What is it has potential energy?
Two ice skaters push off from each other and glide in opposite directions. Which of the following quantities is conserved in the system?
A. Kinetic energy only
B. Momentum only
C. Both momentum and kinetic energy
D. Neither momentum nor kinetic energy
What is: B. Momentum only?
Why is the acceleration of an object thrown upward still negative (downward)?
What is gravity always acts downward, regardless of the object’s direction of motion?
A position vs. time graph of an object shows a curve that gets steeper over time. What does this indicate about the object’s velocity and acceleration?
A. Constant velocity and no acceleration
B. Increasing velocity and constant acceleration
C. Decreasing velocity and negative acceleration
D. Increasing velocity and decreasing acceleration
What is: B. Increasing velocity and constant acceleration?
In an elevator accelerating downward, the normal force on a standing passenger is less than their weight. Explain why.
What is the floor doesn't need to push up as hard since the person is accelerating downward with the elevator?
A ball is dropped from a height and bounces, reaching a lower height after each bounce. Which of the following is true about the system’s mechanical energy?
A. It is conserved during each bounce.
B. It increases after each bounce.
C. It decreases due to energy lost to other forms.
D. It remains constant because total energy is conserved.
What is: C. It decreases due to energy lost to other forms?
A 5 kg object moving at 4 m/s collides with a stationary 10 kg object. After the collision, they stick together. What is their velocity after the collision?
What is: 2 m/s?
An object is dropped from a tall building. Air resistance is not negligible. What happens to its acceleration as it falls?
A. It stays constant at 9.8 m/s²
B. It increases over time
C. It decreases due to air resistance
D. It becomes zero instantly
What is: C. It decreases due to air resistance?
You’re told an object’s acceleration is zero. What can you infer about its velocity?
What is the velocity is constant?
A 10 kg box slides on a horizontal surface with a coefficient of friction of 0.4. What is the frictional force acting on the box?
What is: 40 N?
A student pushes a box across a rough floor at constant speed. Which energy transformation is most directly responsible for the energy leaving the system of the box?
A. Kinetic energy to potential energy
B. Potential energy to kinetic energy
C. Kinetic energy to thermal energy
D. Potential energy to thermal energy
What is C. Kinetic energy to thermal energy?
Why does extending the time of impact (e.g., with airbags) reduce the force experienced?
What is impulse is fixed (change in momentum), so increasing time decreases the average force?
A rock is thrown upward from a bridge and hits the water below 4 seconds later. Which statement about its velocity at impact is correct (ignore air resistance)?
A. It is the same as the initial velocity upward
B. It is zero
C. It is greater than the initial velocity upward
D. It depends only on the height of the bridge
What is: C. It is greater than the initial velocity upward?
Two balls are thrown from the same height, one straight down and one horizontally. Which hits first and why?
What is they hit at the same time because vertical motion is independent of horizontal motion?
A rocket accelerates in the vacuum of space. Explain how this is possible using Newton’s Third Law.
What is the rocket pushes exhaust gases backward, and the gases push the rocket forward with equal and opposite force?
A 2 kg object is lifted to a height of 10 m. What is its gravitational potential energy? done?
What is: 196 J?
In a completely inelastic collision, what happens to the total kinetic energy of the system?
A. It increases
B. It stays the same
C. It decreases, but total momentum is still conserved
D. It is transferred completely into potential energy
What is: C. It decreases, but total momentum is still conserved?
If two projectiles are launched with the same speed but at complementary angles (e.g., 30° and 60°), why do they land at the same range?
What is the horizontal ranges are the same because the product of horizontal velocity and time is equal due to symmetry in projectile motion?