Question

A car attains the velocity of 20m/s in 20 sec. If the mass of car is 1000 kg. Find force applied by the engine​

Answer 1

Answer:

-4000N

Explanation:

Given,

Initial velocity(u)=20ms−1

Final velocity(v)=0

Distance moved(S)=50m

We know,

v2=u2+2aS

0=202+2a×50

−400=100a

a=100−400

a=−4ms−2

Now,

F=ma

F=1000×−4

=−4000N

Answer 2

• initial velocity=u=0m/s
• Final velocity=v=20m/s
• Time=t=20s
• Mass=m=1000kg
• Force=F=?

We know

$\boxed{\sf Acceleration (a)=\dfrac{v-u}{t}}$

Using Newton's second law

$\\ \sf\longmapsto F=ma$

$\\ \sf\longmapsto F=\dfrac{m(v-u)}{t}$

$\\ \sf\longmapsto F=\dfrac{1000(20-0)}{20}$

$\\ \sf\longmapsto F=\dfrac{1000(20)}{20}$

$\\ \sf\longmapsto F=\dfrac{20000}{20}$

$\\ \sf\longmapsto F=1000N$