Question

A ball of mass 0.5 kg, initially at rest, is kicked directly toward a fence from a point 20m away. The velocity of the ball as it leaves the kicker's foot is 18 m/s at an angle of 62 degrees above the horizontal. What is the initial kinetic energy of the ball?

Answer 1

The initial kinetic energy of a 0.5 kg ball kicked at 18 m/s is calculated using the formula KE = 0.5 * m * v^2, resulting in an initial kinetic energy of 81 Joules.

Step-by-step explanation:

The question requires us to calculate the initial kinetic energy of a ball which has been kicked with a certain mass, velocity, and angle. To find the initial kinetic energy, we can use the equation KE = 0.5 * m * v^2, where m is the mass of the ball and v is the speed of the ball. The initial speed given is the total velocity at which the ball is kicked. The angle of the kick is not directly relevant for this calculation because kinetic energy does not depend on the direction of velocity.

In this specific case, the mass (m) of the ball is 0.5 kg and the initial velocity (v) is 18 m/s. Plugging these values into the kinetic energy equation:

KE = 0.5 * 0.5 kg * (18 m/s)^2

KE = 0.25 kg * 324 m^2/s^2

KE = 81 Joules

Therefore, the initial kinetic energy of the ball is 81 Joules.