Question

2. Th
A force 1.ON acts on body of mass 10 kg. As a result the body covers 100 cm in 4 seconds moving along
a straight line. It's initial velocity is
1
F
4.
S
a) 0.5 cms -1
b) 5 cms - 1
1
c) 50 cms -
d)
cms - 1
5
​

Answer 1

Given:-

• Force , F = 1N

• Mass ,m = 10kg

• distance covered ,s = 100cm

• time taken , t = 4s

To Calculate:-

• Initial velocity ,u.

Solution:-

Firstly we convert the unit here

1 m = 100cm

∴ 100cm = 100/100m = 1m

As we know that Force is the product of mass and acceleration.

→ F = m×a

Substitute the value we get

→ 1 = 10 ×a

→ a = 1/10

→ a = 0.1m/s²

therefore the acceleration of the body is 0.1m/s²

Now Using 2nd equation of motion

→s = ut +1/2at²

Substitute the value we get

→ 1 = u×4 + 1/2×0.1×4²

→ 1 = u×4 +1/2× 0.1×16

→ 1= u×4 + 0.1 × 8

→ 1 = u×4 + 0.8

→ 1-0.8 = u×4

→ 0.2 = u×4

→ u = 0.2/4

→ u = 0.05m/s

Now converting the speed into cm/s

1m = 100cm

∴ 0.05cm = 0.05×100 = 5cm/s

∴ The initial velocity of the body is 5cm/s.

Hence, Option (b) is the correct answer