Question

A body of mass 2 kg moves with acceleration 3 m/s. The change in momentum in one second is
(1) 2 /3 kg m/s
(2) 3/2 kg m/s
(3) 6 kg m/s
(4) None of these​

Answer 1

Answer

Option (3) is correct

ΔP = 6 Kg-m/s

Given

A body of mass 2 kg moves with acceleration 3 m/s

To Find

Change in momentum in 1 second

Formula Used

$\rm Change\ in\ momentum,\\\\\to \rm \Delta P=m(v-u)$

Solution

Mass , m = 2 kg

Acceleration , a = 3 m/s²

Time , t = 1 s

ΔP = ? Kg-m/s

We know that , " Acceleration is defined as rate of change in velocity "

$\to \rm a=\dfrac{v-u}{t}\\\\\to \rm 3=\dfrac{v-u}{1}\\\\\to \bf v-u=3\ m/s$

Now , apply for change in momentum ,

$\to \rm \Delta P=m(v-u)\\\\\to \rm \Delta P=2(3)\\\\\to \bf \Delta P=6\ Kg-m/s$

Answer 2

Given ,

Mass (m) = 2 kg

Acceleration (a) = 3 m/s²

Time (t) = 1 sec

We know that ,

Acceleration (a) = (v - u)/t

Thus ,

3 = (v - u)/1

v - u = 3

Now ,

ΔP = m(v - u)

Where ,

ΔP = Change in momentum

Thus ,

ΔP = 2 × 3

ΔP = 6 kg•m/s

$\sf \therefore \underline{The \: change \: in \: momentum \: of \: a \: body \: is \: 6 \: kg.m {s}^{ - 1} }$