Question

a body of mass 2 kg is at rest what should be the magnitude of force which will make the body move with the speed of 30 metre per second at the end of one second​

Answer 1

Given :

▪ Mass of body = 2kg

▪ Initial velocity = zero (i.e., rest)

▪ Final velocity = 30mps

▪ Time interval = 1s

To Find :

▪ External force applied on the body.

Concept :

✒ This question is completely based on concept of Newton's second law of motion.

✒ Net force applied on the body is given by change in momentum per unit time.

Mathematically,

$\bigstar\:\underline{\boxed{\bf{\pink{F=\dfrac{\Delta P}{\Delta t}=\dfrac{m(v-u)}{t}}}}}$

• F denotes applied force
• m denotes mass of body
• u denotes initial velocity
• v denotes final velocitu
• t denotes time interval

Calculation :

$\implies\sf\:F=\dfrac{m(v-u)}{t}\\ \\ \implies\sf\:F=\dfrac{2(30-0)}{1}\\ \\ \implies\underline{\boxed{\bf{\purple{F=60N}}}}$