Search any question & find its solution
Question:
Answered & Verified by Expert
A body of mass $2 \mathrm{~kg}$ starts from rest and moves with uniform acceleration. It acquires a velocity $20 \mathrm{~ms}^{-1}$ in $4 \mathrm{~s}$. The power exerted on the body in $2 \mathrm{~s}$ in watts is
Options:
Solution:
1778 Upvotes
Verified Answer
The correct answer is:
$100$
$m=2 \mathrm{~kg}, u=0, v=20 \mathrm{~m} / \mathrm{s}, t=4 \mathrm{sec}$
Acceleration $a=\frac{v-u}{t}=\frac{20-0}{4}=5 \mathrm{~m} / \mathrm{s}^2$
$\therefore \quad$ Force applied $F=m a=2 \times 5=10 \mathrm{~N}$
Velocity at the end of $2 \mathrm{sec}$
$$
v=u+a t=0+5 \times 2=10 \mathrm{~m} / \mathrm{s}
$$
$\therefore \quad$ Power $P=F v=10 \times 10=100$ watt
Acceleration $a=\frac{v-u}{t}=\frac{20-0}{4}=5 \mathrm{~m} / \mathrm{s}^2$
$\therefore \quad$ Force applied $F=m a=2 \times 5=10 \mathrm{~N}$
Velocity at the end of $2 \mathrm{sec}$
$$
v=u+a t=0+5 \times 2=10 \mathrm{~m} / \mathrm{s}
$$
$\therefore \quad$ Power $P=F v=10 \times 10=100$ watt
Looking for more such questions to practice?
Download the MARKS App - The ultimate prep app for IIT JEE & NEET with chapter-wise PYQs, revision notes, formula sheets, custom tests & much more.