Question

A constant force acting on a body of mass of 5 kg change its speed from `5ms^(-1) "to" 10ms^(-1)` in 10 s without changing the direction of motion. The force acting on the body is
A. 1.5N
B. 2N
C. 2.5N
D. 5N

Answer 1

Correct Answer - C
Here, 5kg, u=`5ms^(-1), v=10ms^(-1), t=10s` using v=u+at
`a=(v-u)/(t)=((10-5)ms^(-1))/(10s)=0.5ms^(-2)`
As, F=ma `therefore F=(5kg)(0.5ms^(-2))=2.5N`