Mechanics - Work, Energy & Power
Q. A 10 kg object is moving with a velocity of 4 m/s. What is its total mechanical energy if it is at a height of 5 m? (2020)
-
A.
120 J
-
B.
140 J
-
C.
100 J
-
D.
80 J
Solution
Total Mechanical Energy = Kinetic Energy + Potential Energy = (1/2 * 10 kg * (4 m/s)²) + (10 kg * 9.8 m/s² * 5 m) = 80 J + 490 J = 570 J
Correct Answer: B — 140 J
Learn More →
Q. A 2 kg object is dropped from a height of 20 m. What is its speed just before it hits the ground? (g = 10 m/s²) (2023)
-
A.
20 m/s
-
B.
10 m/s
-
C.
15 m/s
-
D.
5 m/s
Solution
Using the formula v = √(2gh) = √(2 * 10 m/s² * 20 m) = √400 = 20 m/s
Correct Answer: A — 20 m/s
Learn More →
Q. A 3 kg object is moving with a velocity of 6 m/s. What is its momentum? (2021)
-
A.
18 kg m/s
-
B.
12 kg m/s
-
C.
9 kg m/s
-
D.
6 kg m/s
Solution
Momentum (p) = mv = 3 kg * 6 m/s = 18 kg m/s
Correct Answer: A — 18 kg m/s
Learn More →
Q. A spring is compressed by 0.2 m and has a spring constant of 500 N/m. What is the potential energy stored in the spring? (2023)
-
A.
10 J
-
B.
5 J
-
C.
20 J
-
D.
2 J
Solution
Potential Energy in Spring (PE) = 1/2 kx^2 = 1/2 * 500 N/m * (0.2 m)^2 = 10 J
Correct Answer: A — 10 J
Learn More →
Q. If a force of 10 N moves an object 5 m in the direction of the force, what is the work done? (2020)
-
A.
50 J
-
B.
10 J
-
C.
5 J
-
D.
25 J
Solution
Work Done (W) = Force (F) * Distance (d) = 10 N * 5 m = 50 J
Correct Answer: A — 50 J
Learn More →
Q. If a machine does 200 J of work in 5 seconds, what is its power? (2022)
-
A.
40 W
-
B.
50 W
-
C.
20 W
-
D.
30 W
Solution
Power (P) = Work Done (W) / Time (t) = 200 J / 5 s = 40 W
Correct Answer: B — 50 W
Learn More →
Showing 1 to 6 of 6 (1 Pages)
