Physics Practice: Work, Power and Energy (Mock Test 3 - Advanced)
1. A body of mass $m$ is falling from a height $h$. At a point where it has fallen a distance $h/3$, the ratio of its Kinetic Energy to Potential Energy is:
2. Two bodies $A$ and $B$ have masses $m$ and $4m$ respectively. If they have the same Kinetic Energy, the ratio of their linear momenta $P_A : P_B$ is:
3. Why is the work done by a centripetal force always zero in a circular path?
4. An engine develops $10 \text{ kW}$ of power. How much time will it take to lift a mass of $200 \text{ kg}$ to a height of $40 \text{ m}$? ($g = 10 \text{ m/s}^2$)
5. In a nuclear reaction, if $10 \text{ mg}$ of mass is completely converted into energy, the energy released is: ($c = 3 \times 10^8 \text{ m/s}$)
6. A spring is compressed by $x$. The work done in compressing it is $W$. The extra work required to compress it further by $x$ is:
7. When a conservative force does positive work on a body, the Potential Energy of the body:
8. A moving car is stopped by applying brakes. The kinetic energy is primarily converted into:
9. If a body of mass $m$ is moved up an inclined plane of length $L$ and height $h$, the work done against gravity is:
10. Two masses $1 \text{ g}$ and $9 \text{ g}$ are moving with equal linear momentum. The ratio of their Kinetic Energies is:
11. In which of the following cases is the work done negative?
12. A bullet of mass $10 \text{ g}$ leaves a rifle at a speed of $400 \text{ m/s}$. Its Kinetic Energy is:
13. The potential energy of a body is given by $U = ax^2 - bx$. The force acting on the body is:
14. Which form of energy is possessed by a compressed gas?
15. A force $F = (5\hat{i} + 3\hat{j}) \text{ N}$ produces a displacement $S = (2\hat{i} - 1\hat{j}) \text{ m}$. The work done is:
16. The kilowatt-hour ($1 \text{ kWh}$) is a unit of energy used in domestic billing. It equals:
17. In a simple pendulum, the transformation of energy at the extreme position is:
18. A weightlifter lifts a $200 \text{ kg}$ weight to a height of $2 \text{ m}$ and holds it there for $10 \text{ s}$. The work done by him in holding the weight is:
19. If the momentum of a body decreases by $20\%$, its Kinetic Energy decreases by:
20. Mechanical energy is the sum of: