Question

A truck of mass 5000 kg moving with a velocity of mass 90 km/h hits a wall

and comes to rest in 25 second find the force exerted by the car on the wall.​

Answer 1

Initial Velocity= 90km/h=>25m/s

Final Velocity=0 =>(because it comes to rest)

Mass=5000Kg

Time=25 seconds

To find out Acceleration,

v=u+at

Substitute the Values

0=25m/s+(a)(25sec)

0=25m/s+25a

-25a=25

a=25/-25

a=-1m/s sq

Now,Calculate the force

F=ma

=5000kg×(-1m/s)

=5000kg×(-1m/s)F=(-5000N)

Answer 2

Given :-

A truck of mass 5000 kg moving with a velocity of mass 90 km/h hits a wall and comes to rest in 25 second

To find :-

The force exerted by the car on the wall.

Solution :-

• Mass of truck (m) = 5000kg
• Initial velocity (u) = 90km/h
• Final velocity (v) = 0
• Time taken (t) = 25 sec

→ Initial velocity = 90km/h

→ u = 90 × 5/18

→ u = 25m/s

According to first equation of motion

→ v = u + at

→ 0 = 25 + a × 25

→ 25a = - 25

→ a = - 1 m/s²

Now,

• As we know that

→ Force = mass × acceleration

→ F = m × a

→ F = 5000 × (-1)

→ F = - 5000N

Hence,

• The force exerted by the car on the wall is - 5000N
• Minus shows force exerted in opposite direction