Question

an object with a mass of 10kg moves at a constant velocity of 10m/s. A constant force then acts for 4 sec on the object and gives it a speed of 2m/sec in opposite direction. The force acting on body

Answer 1

here is your answer....

Answer 2

Force acting on body is -30 N

Explanation

Given that an object with a mass of 10kg moves at a constant velocity of 10m/s. A constant force then acts for 4 sec on the object and gives it a speed of 2m/sec in opposite direction.

We have to find force acting on body.

Solution

Here we have ;

• Mass of object (M) = 10 kg
• Initial velocity (u) = 10 m/s
• Time (t) = 4 s
• Final velocity (v) = -2 m/s [As it's in opposite direction]

At first using 1st equation of motion :-

→ v = u + at

→ -2 = 10 + a * 4

→ -2 - 10 = 4a

→ -12 = 4a

→ a = -12/4

→ a = -3 m/s²

Now using Newton's 2nd law :-

→ Force = mass * acceleration

→ Force = 10 * (-3)

→ Force = -30

→ Force = -30 N

[Force in negative means that force is acting in opposite direction]

Hence,

Force acting on body is 30 N in opposite direction.