Question

The velocity of a body of mass 20kg decreases from 20 m/sec to 5 m/sec in a distance of 100m . Force on the body is?

Answer 1

Heya user !!!

Here's the answer you are looking for

Initial velocity (u) = 20m/s

Final velocity (v) = 5m/s

Distance travelled (s) = 100m

Using the 3rd equation of motion,

v² - u² = 2as where a is the acceleration

5² - 20² = 2a (100)

25 - 400 = 200a

- 375 = 200a

a = - 375 / 200 = - 1.875

So, the acceleration is - 1.875 m/s²

Now,
Force = mass × acceleration

= 20 kg × (- 1.875) m / s²

= -37.5 kgm/s²

= -37.5 N

(negative sign indicates that the force is opposite to the direction of motion.)

Therefore, the force on the body is - 37.5 N



★★ HOPE THAT HELPS ☺️ ★★

Answer 2

here from eq. of motion,
v2 = u2 + 2as
=> 5^2 = 20^2 + 2a×100
=> 200a = 25-400= -375
=> a = -375/200 = -15/8 m/s^2
here, negative sign shows deceleration
F = ma = 20×(15/8) =75/2 =37.5 N
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I hope this helps you...