# LET Reviewer - PHYSICAL SCIENCE (MECHANICS)

Majorship LET Reviewer LET Reviewer for Physical Science
PRACTICE TEST IN PHYSICAL SCIENCE (MECHANICS)

1. The radius of the path of an object in uniform circular motion is doubled. The centripetal force needed if its speed remains the same is ________.
A. Four times as before
B. Half as great as before
C. Twice as much
D. Three times as much

2. Car A has a mass of 1000kg and a speed of 60km/hr. car B has amass of 2000kg and a speed of 30km/hr. compare the kinetic energy foe car A with that of car B.
A. Half as much
B. Four times as much
C. Equal
D. Twice as much

3. What would be the horizontal line in a position-time graph means?
A. Changing position, constant velocity
B. Constant position, constant velocity
C. Changing position, increase velocity
D. Constant position, zero velocity

4. What is the car’s acceleration if ten seconds after the starting from rest; it is moving at 40m/s?
A. 4.0m/s^2
B. 10m/s^2
C. 2.5m/s^2
D. 0.25m/s^2

5. A heavy object and a light object are released from the rest at the same height and time in a vacuum. As they fall, they have equal ________.
A. Weights
B. Moments
C. Acceleration
D. Energies

6. Airplanes are designed with pointed nose and thin tails in order to__________.
A. Produce fluid friction
B. Reduce drag
C. Increase the lift of the wing
D. Lessen the forward thrust

7. A stone was thrown upward from the roof, at the same time that an identical stone was dropped from there. The two stones will ________.
A. Have the same velocity upon reaching the ground
B. Take the same time to reach the ground
C. Have they same acceleration when they reach the ground
D. Reach the ground at the same time

8. In a pair of scissors, the fulcrum is located at the ________.
A. Handle
B. Screw
D. Sharp edges

9. What kind of energy is possessed by water falling from a dam?
A. Potential
B. Kinetic
C. Accelerating
D. Interacting

10. If an object were equipped with a speedometer and allowed to fall freely on a planet where the acceleration due to gravity is 20m/s2, by, how much will the reading on the speedometer increase each second?
A. 30m/s
B. 20m/s
C. 40m/s
D. 10m/s

11. According to the kinetic molecular theory, liquids are similar in solids in that _______.
A. Their molecules are arrange in a regular manner
B. The motion of their particles changes with temperature
C. The motion of their particles cannot be determined
D. There is very little space in their molecules

12. When the solid block of materials is cut in half, its density is ________.
A. Unchanged
B. Halves
C. Doubled
D. Tripled

13. A ball is launched at an angle of 60 degrees from the horizontal. What do you call the horizontal distance traveled by the ball?
A. Trajectory
B. Projectile
C. Range
D. Hyperbola

14. Which of the following is TRUE about an object thrown horizontally?
A. The vertical distance traveled increases uniformly
B. The horizontal motion is uniformly accelerated
C. The horizontal component of velocity increases
D. The velocity of the subject increases

15. In the absence of the air resistance, a projectile has a maximum range when thrown at an angle of __________.
A. 90 degrees
B. 60 degrees
C. 30 degrees
D. 45 degrees

16. A 400 N woman stands on top of a very tall ladder so she is one earth radius above the earth’s surface. How much does she weights?
A. 100N
B. Zero
C. 200N
D. 400N

17. What must be the minimum length of the plane mirror in order for you to see a full view of yourself?
B. One-fourth
C. One-half
D. Three-fourths

18. A rifle recoils from firing a bullet. The speed of the recoil is slow because ___________.
A. The force against the rifle is less
B. The rifle has more mass than the bullet
C. The impulse on the rifle is less
D. The momentum of the rifle is unchanged.

19. Which statements differentiate weight for mass?
A. Weight is distance from a reference point
B. Weight has volume, mass has none
C. Weight is a full of gravity, mass is space occupied
D. Weight is a force while mass is amount of matter

20. Who established the relationship between the volume of a gas and the pressure when the temperature is constant?
A. Blaise Pascal
B. Robert Boyle
C. Lavoisier
D. Archimedes

21. Which of the following quantities is a scalar quantity?
a. momentum
b. work
c. force
d. acceleration

22. An airplane travels east for 2 hours at a rate of 500km/h. Which of the following quantities is a vector?
a. the time of travel
b. the displacement
c. the distance traveled
d. the speed of the plane

23. Which of the following is the best definition of velocity?
a. It is a description of the motion of a body.
b. It is a measure of how fast a body is moving.
c. It is the speed of a body and its direction of motion.
d. It is equal to the distance traveled divided by the time of travel.

24. The speedometer of a car gives you a reading of the car’s
a. instantaneous speed
b. instantaneous velocity
c. average speed
d. average velocity

25. Acceleration is defined as the change in
a. velocity divided by the time interval
b. distance divided by the time interval
c. time it takes to move from one place to another place
d. time it takes to move from one speed to another speed

26. Which of the following situations describes a body that is accelerating?
a. a truck that is at rest
b. a car rounding a curve at constant speed
c. a bicycle moving at constant speed along a straight highway
d. none of the above

27. Which of the following statements is always true?
a. when the acceleration is constant, the velocity is zero
b. when the acceleration is zero, the velocity is also zero
c. when the velocity is constant, the acceleration is zero
d. when the instantaneous velocity is zero, the acceleration is also zero

28. A truck is moving along a straight highway. As it approaches an intersection, the driver steps on the brakes, bringing the car to a complete stop. Which of the following statements is true about the motion of the truck?
a. the velocity and acceleration have opposite directions
b. the velocity and acceleration have the same directions
c. the velocity and acceleration of the truck are both constant
d. none of the above

29. The acceleration of a stone thrown upward is
a. the same as that of a stone thrown downward
b. greater than that of a stone thrown downward
c. smaller than that of a stone thrown downward
d. zero until it reaches the highest point in its motion

30. For an object that is dropped from rest,
a. the speed is proportional to the time of fall
b. the acceleration is proportional to the time of fall
c. the distance traveled is proportional to the time of fall
d. all of the above

31. If a freely falling object were somehow equipped with a speedometer, its speed reading wound increase each second by
d. a variable amount

32. An object at rest maintains its state of rest unless acted upon by a net force because of its
a. mass
b. momentum
c. inertia
d. energy

33. An object in uniform motion maintains its state of motion unless acted upon by a net force because of its
a. mass
b. momentum
c. inertia
d. energy

34. A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is pulled quickly. The reason this can be done is that
a. the milk carton has inertia
b. the milk carton has very little weight
c. gravity pulls very hard on the milk carton
d. there are action and reaction forces

35. If the force of gravity suddenly stopped acting on the planets, they would
a. spiral slowly toward the sun
b. spiral slowly away from the sun
c. fly straight away from the sum
d. move in a straight line tangent to their orbit 