Question

Your mass is 50 kg. You gain a running speed of 4 m/s in 2 seconds after starting from the rest. Choose the correct statement

A. You applied a force of 100 N on your body
B. Ground friction force applied a force of 100 N on your body
C. You applied a force of 200 N on your body
D. Ground friction force applied a force of 200 N on your body​

Answer 1

Answer:

Ground friction force applied a force of 100 N on your body

Answer 2

The correct statement is B. Ground friction force applied a force of 100 N on your body.

• When a person moves, the body applies force on the ground. The frictional force exerted by the ground on our feet helps us to move forward.
• According to the question, we gain a running speed of 4 m/s in 2 seconds after starting from the rest

    ⇒ The acceleration a = Final velocity - Initial velocity / time interval

         = 4 - 0 / 2

         = 2m/s²

• According to newton's law of motion, the force exerted F = ma
• Since our mass is 50kg, the force exerted by us on the floor is 50 X 2 = 100 N.

• The friction force exerts equal and opposite force on our body (Newton's 3rd law).