Kinetic Energy

Question

A body of mass 4 kg moving with a velocity of 10 m/s is brought to rest by a constant force in 5 seconds. What is the work done by the force?

RankGuru · Accepted Answer

1. **Work-Energy Theorem**: The work done by all forces acting on a particle is equal to the change in its kinetic energy ($W = \Delta K$).
2. **Initial Kinetic Energy ($K_i$)**:
   - $K_i = \frac{1}{2} m v^2 = \frac{1}{2} 	imes 4 	imes (10)^2 = 2 	imes 100 = 200$ J.
3. **Final Kinetic Energy ($K_f$)**:
   - Since it is brought to rest, $K_f = 0$ J.
4. **Work Calculation**:
   - $W = K_f - K_i = 0 - 200 = -200$ J.
5. **Interpretation**: The negative sign indicates that the force is doing work in a direction opposite to the displacement (resistive force).

Kinetic Energy

Select the correct option:

Solution

🔒 Solution Hidden from View

More kinetic energy Practice Questions

Two bodies of different masses possess the same magnitude of linear momentum while moving in a strai...

A hockey puck of mass 0.2 kg slides across ice and its speed decreases steadily from 12 m/s to 4 m/s...

A disc with moment of inertia 0.5 kg·m² rotates about its central axis at an angular velocity of 4 r...

When the absolute temperature of a fixed sample of ideal gas is raised from 300 K to 600 K, by what ...

Two containers hold helium and oxygen respectively at the same absolute temperature, so how do the a...

Two particles, a proton and an electron, are each given the same kinetic energy in a laboratory, and...

About This Question

Solution