Problem:
A block of mass 2kg is lying on a frictionless table. A force of 8N is applied to it for 12s. Calculate its kinetic energy.

Solution:
To solve this problem, we need to understand the concept of kinetic energy and the relationship between force, mass, and acceleration.

Kinetic Energy:
Kinetic energy is the energy possessed by a moving object due to its motion. It depends on the mass and velocity of the object and is given by the formula:
Kinetic Energy (KE) = 0.5 * mass * velocity^2.

Force and Acceleration:
According to Newton's second law of motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. The formula is given as:
Force (F) = mass (m) * acceleration (a).

Calculating Acceleration:
Since the block is on a frictionless table, there is no opposing force to the applied force of 8N. Therefore, the net force acting on the block is equal to the applied force. We can use Newton's second law of motion to calculate the acceleration:
8N = 2kg * a
a = 4 m/s^2.

Calculating Velocity:
To calculate the velocity of the block, we need to know the initial velocity. Assuming the block was initially at rest, its initial velocity (u) is 0. We can use the formula of motion to calculate the final velocity (v):
v = u + at
v = 0 + 4 m/s^2 * 12s
v = 48 m/s.

Calculating Kinetic Energy:
Now that we have the mass (2kg) and velocity (48 m/s), we can calculate the kinetic energy using the formula:
KE = 0.5 * m * v^2
KE = 0.5 * 2kg * (48 m/s)^2
KE = 0.5 * 2kg * 2304 m^2/s^2
KE = 2304 J.

Therefore, the kinetic energy of the block is 2304 Joules.

2,304 Answer