Question

A man kicks a football of mass 0.3 kg and it gains a speed of 10m/s if his foot remains in constant for 10m/s then find a. impluse of the force b. average force​

Answer 1

Correct answer

A man kicks a football of mass 0.3 kg and it gains a speed of 10m/s if his foot remains in constant for 10ms(milliseconds) then find a. impluse of the force b. average force

Answer

Given :

Mass of the ball = 0.3kg.

Final velocity = 10m/s.

Initial velocity = zero.

Time = 10ms = 10 × 10¯³sec.

To find :

(a) Impluse of the force

(b) Average force

Solution :

(a) Impluse is a impact of force. Impluse is equal to change in momentum i.e.,

$\bf l = \Delta P = mv_f - mv_i$

where,

• m denotes mass
• v$\sf _f$ denotes final velocity
• v$\sf _i$ denotes initial velocity

$\dashrightarrow \sf l = mv_f - mv_i$

$\dashrightarrow \sf l = (0.3)(10) - (0.3)(0)$

$\dashrightarrow \sf l = 3 - 0$

$\dashrightarrow \sf l = 3 kg \: {ms}^{ - 1}$

Thus, Impluse of the force is 3 Kg m/s.

(b) Using Newton's second law of motion that is,

Net force acting on an object is directly proportional to the rate of change of it's linear momentum,

$\dashrightarrow \bf F = \dfrac{\Delta P}{t}$

$\dashrightarrow \sf F = \dfrac{3}{10 \times {10}^{ - 3} }$

$\dashrightarrow \sf F = 3 \times {10}^{2}$

$\dashrightarrow \sf F = 300N$

Thus, Average force of the ball is 300N.