Q. A 3 kg object is lifted to a height of 4 m. What is the work done against gravity?
A.12 J
B.24 J
C.36 J
D.48 J
Solution
Work done = mgh = 3 * 9.8 * 4 = 117.6 J.
Correct Answer: B — 24 J
Q. A 3 kg object is lifted to a height of 5 m. What is the work done against gravity? (g = 9.8 m/s²)
A.147 J
B.294 J
C.441 J
D.588 J
Solution
Work done = mgh = 3 kg × 9.8 m/s² × 5 m = 147 J.
Correct Answer: B — 294 J
Q. A 3 kg object is moving with a speed of 10 m/s. What is its kinetic energy?
A.150 J
B.300 J
C.450 J
D.600 J
Solution
Kinetic energy = 0.5mv² = 0.5 * 3 * (10)² = 150 J.
Correct Answer: B — 300 J
Q. A 3 kg object is moving with a speed of 4 m/s. What is its kinetic energy?
A.12 J
B.24 J
C.36 J
D.48 J
Solution
Kinetic energy = 0.5mv² = 0.5 * 3 * (4)² = 24 J.
Correct Answer: B — 24 J
Q. A 3 kg object is moving with a speed of 4 m/s. What is its total mechanical energy?
A.24 J
B.32 J
C.48 J
D.60 J
Solution
Total mechanical energy = KE + PE. Assuming it is at ground level, PE = 0. KE = 0.5mv² = 0.5 * 3 * (4)² = 24 J.
Correct Answer: B — 32 J
Q. A 3 kg object is moving with a speed of 5 m/s. What is its kinetic energy?
A.15 J
B.25 J
C.35 J
D.45 J
Solution
Kinetic energy is given by KE = 0.5mv² = 0.5 * 3 * (5)² = 37.5 J, approximately 35 J.
Correct Answer: B — 25 J
Q. A 3 kg object is moving with a velocity of 4 m/s. What is its kinetic energy?
A.12 J
B.24 J
C.36 J
D.48 J
Solution
Kinetic Energy = 0.5 × mass × velocity² = 0.5 × 3 kg × (4 m/s)² = 24 J.
Correct Answer: B — 24 J
Q. A 3 kg object is pushed with a force of 12 N over a distance of 4 m. If the object starts from rest, what is its final speed? (Assume no friction)
A.2 m/s
B.3 m/s
C.4 m/s
D.5 m/s
Solution
Work done = Force × Distance = 12 N × 4 m = 48 J. Kinetic energy = 0.5 × mass × v²; 48 J = 0.5 × 3 kg × v²; v² = 32; v = 4 m/s.
Correct Answer: C — 4 m/s
Q. A 4 kg object is at rest on a table. What is the force of static friction acting on it?
A.0 N
B.4 N
C.40 N
D.10 N
Solution
If the object is at rest and no external force is applied, the static friction force is 0 N.
Correct Answer: A — 0 N
Q. A 4 kg object is at rest on a table. What is the force of static friction if no external force is applied?
A.0 N
B.4 N
C.40 N
D.None of the above
Solution
If no external force is applied, the force of static friction is 0 N.
Correct Answer: A — 0 N
Q. A 4 kg object is lifted to a height of 3 m. What is the increase in gravitational potential energy? (g = 9.8 m/s²)
A.117.6 J
B.117 J
C.120 J
D.150 J
Solution
Potential energy increase = mgh = 4 kg × 9.8 m/s² × 3 m = 117.6 J.
Correct Answer: A — 117.6 J
Q. A 4 kg object is lifted to a height of 3 m. What is the increase in gravitational potential energy?
A.12 J
B.24 J
C.36 J
D.48 J
Solution
Increase in potential energy = mgh = 4 kg × 9.8 m/s² × 3 m = 117.6 J.
Correct Answer: B — 24 J
Q. A 4 kg object is moving with a velocity of 2 m/s. What is the change in momentum if the object comes to a stop?
A.0 kg·m/s
B.4 kg·m/s
C.8 kg·m/s
D.2 kg·m/s
Solution
Change in momentum = final momentum - initial momentum = 0 - (4 kg * 2 m/s) = -8 kg·m/s.
Correct Answer: C — 8 kg·m/s
Q. A 4 kg object is pulled with a force of 20 N. If the frictional force is 4 N, what is the net force acting on the object?
A.16 N
B.20 N
C.24 N
D.4 N
Solution
Net force = applied force - frictional force = 20 N - 4 N = 16 N.
Correct Answer: A — 16 N
Q. A 4 kg object is pushed with a force of 20 N over a distance of 3 m. If the object starts from rest, what is its final speed? (Assume no friction)
A.2 m/s
B.3 m/s
C.4 m/s
D.5 m/s
Solution
Work done = Force × Distance = 20 N × 3 m = 60 J. Kinetic energy = 0.5 × m × v². 60 J = 0.5 × 4 kg × v². v² = 30, v = √30 ≈ 5.48 m/s.
Correct Answer: C — 4 m/s
Q. A 4 kg object is pushed with a force of 20 N over a distance of 3 m. If the object starts from rest, what is its final speed?
A.2 m/s
B.3 m/s
C.4 m/s
D.5 m/s
Solution
Work done = Force × Distance = 20 N × 3 m = 60 J. K.E = 0.5 × m × v², 60 J = 0.5 × 4 kg × v², v = 3.87 m/s.
Correct Answer: C — 4 m/s
Q. A 4 kg object is pushed with a force of 20 N. If the frictional force is 4 N, what is the acceleration of the object?
A.4 m/s²
B.5 m/s²
C.6 m/s²
D.7 m/s²
Solution
Net force = applied force - friction = 20 N - 4 N = 16 N. Acceleration a = F/m = 16 N / 4 kg = 4 m/s².
Correct Answer: B — 5 m/s²
Q. A 4 kg object is subjected to a net force of 12 N. What is the acceleration of the object?
A.2 m/s²
B.3 m/s²
C.4 m/s²
D.5 m/s²
Solution
Using F = ma, a = F/m = 12 N / 4 kg = 3 m/s².
Correct Answer: B — 3 m/s²
Q. A 5 kg block is placed on a surface with a coefficient of static friction of 0.6. What is the maximum static friction force before the block starts to move?
A.30 N
B.20 N
C.15 N
D.25 N
Solution
Maximum static friction force = μs * N = 0.6 * (5 kg * 9.8 m/s²) = 29.4 N, approximately 30 N.
Correct Answer: A — 30 N
Q. A 5 kg block is resting on a frictionless surface. If a force of 10 N is applied to it, what will be its acceleration?
A.1 m/s²
B.2 m/s²
C.5 m/s²
D.10 m/s²
Solution
Using Newton's second law, F = ma, we have a = F/m = 10 N / 5 kg = 2 m/s².
Correct Answer: B — 2 m/s²
Q. A 5 kg block is resting on a horizontal surface. What is the normal force acting on the block?
A.5 N
B.10 N
C.15 N
D.20 N
Solution
The normal force equals the weight of the block, which is mass times gravity: 5 kg * 9.8 m/s² = 49 N.
Correct Answer: B — 10 N
Q. A 5 kg object is at rest on a surface. If a horizontal force of 15 N is applied, what is the object's acceleration? (Assume friction is negligible)
A.2 m/s²
B.3 m/s²
C.4 m/s²
D.5 m/s²
Solution
Using F = ma, a = F/m = 15 N / 5 kg = 3 m/s².
Correct Answer: B — 3 m/s²
Q. A 5 kg object is dropped from a height of 10 m. What is the total mechanical energy just before it hits the ground?
A.0 J
B.50 J
C.100 J
D.200 J
Solution
Total mechanical energy is conserved. At height, PE = mgh = 5 * 9.8 * 10 = 490 J. Just before hitting the ground, total energy = 490 J.
Correct Answer: C — 100 J
Q. A 5 kg object is lifted to a height of 10 m. What is the potential energy gained by the object?
A.50 J
B.100 J
C.150 J
D.200 J
Solution
Potential energy (PE) = mgh = 5 kg * 9.8 m/s² * 10 m = 490 J.
Correct Answer: B — 100 J
Q. A 5 kg object is lifted to a height of 10 m. What is the work done against gravity?
A.50 J
B.100 J
C.150 J
D.200 J
Solution
Work done against gravity is W = mgh = 5 * 9.8 * 10 = 490 J.
Correct Answer: D — 200 J
Q. A 5 kg object is lifted to a height of 3 m. What is the work done against gravity?
A.15 J
B.30 J
C.45 J
D.60 J
Solution
Work done against gravity is W = mgh = 5 * 9.8 * 3 = 147 J.
Correct Answer: B — 30 J
Q. A 5 kg object is moving with a velocity of 10 m/s. What is its kinetic energy?
A.25 J
B.50 J
C.100 J
D.250 J
Solution
Kinetic energy (KE) = 0.5 * mass * velocity² = 0.5 * 5 * (10)² = 250 J.
Correct Answer: C — 100 J
Q. A 5 kg object is moving with a velocity of 3 m/s. What is its kinetic energy?
A.22.5 J
B.30 J
C.45 J
D.60 J
Solution
Kinetic Energy = 0.5 × mass × velocity² = 0.5 × 5 kg × (3 m/s)² = 22.5 J.
Correct Answer: A — 22.5 J
Q. A 5 kg object is subjected to a net force of 15 N. What is its acceleration?
A.2 m/s²
B.3 m/s²
C.4 m/s²
D.5 m/s²
Solution
Using F = ma, a = F/m = 15 N / 5 kg = 3 m/s².
Correct Answer: B — 3 m/s²
Q. A 5 kg object is subjected to a net force of 15 N. What is the object's acceleration?
