Question

A body of mass 300 gm is at rest. What force
in Newton will you have to apply to move it
through 200 cm in 10 sec.?
A) Zero
B) 12 Newton
C) 1.2 Newton
D) 0.12 Newton​

Answer 1

Given:-

• Initial velocity of body (u) = 0m/s

• Mass of the body (m) = 300g = 0.3kg

• Distance traveled = 200cm = 200/100=2m

• Time taken (t) = 10sec.

To Find:-

• Force apply to move it (F).

Solution:-

Firstly we calculate the acceleration of the body

So, By Using 2nd equation of motion

⟹s = ut +1/2at².

Put the value ,we get

⟹ 2 = 0×10+1/2×a×10²

⟹ 2 = 0+ 1/2×a×100

⟹ 2 = 50×a

⟹ 2/50 = a

⟹ a = 0.04m/s²

The acceleration of the body is 0.004m/s²

Now ,we know that Force is the product of mass and acceleration

⟹ F = m×a

Put the value , we get

⟹ F = 0.3×0.04

⟹ F = 0.012 N

∴ The Force apply to move the body is 0.012N

Answer 2

Explanation:

Using second equation of motion,

s = ut + 1/2 at²

Given: s is 200 cm or 2 m, t is 10 sec, u is 0 m/s and mass is 300 gm or 0.3 kg.

Substitute the values,

→ 2 = (0)(10) + 1/2 * a * (10)²

→ 2 = 0 + 100/2 × a

→ 2 = 50a

→ 0.04 = a

Hence, the acceleration is 0.04 m/s².

Now,

Force = Mass × Acceleration

Substitute the values,

→ Force = 0.3 x 0.04

→ Force = 0.012 N

Hence, the applied force is 0.012 N.