Question

The average force that is necessary to stop a hammer with 25 Newton-sec momentum in 0.05 sec, expressed in Newtons is

• A. 500
• B. 125
• C. 50
• D. 25

Answer 1

The correct option is A 500

The initial momentum of hammer is $mu=25Ns$
The final momentum of hammer is $mv=0Ns$
Time required to stop the hammer is $t=0.05s$
According to Newton's second law of motion
$F=\frac{mv-mu}{t}$
$F=\frac{0-25}{0.05}=-500N$
The negative sign indicates the force acts in opposite direction.
The average force that is necessary to stop a hammer is $F=500N$.