Question

A force of 20 N acting on a body of
mass
is found to double its
velocity in 8 s. Find its initial velocity
10 kg​

Answer 1

• Question

A force of 20 N is acting on a body of mass 10 kg is found to double its velocity in 8 s. Find its initial velocity.

Answer

$\purple{\bigstar}$ Initial velocity $\leadsto$ $\boxed{\sf{\red{16~m/s}}}$

• Given

• Force (F) = 20 N
• Mass (m) = 10 kg
• Time (t) = 8 s
• Final velocity (v) is found to be double of the initial velocity.

• To find

• Initial velocity (u)

• Concept

• For finding the initial velocity, firstly find the acceleration by using F = ma.
• Then by using the first equation of motion we will find the Initial velocity

• Solution

$\purple{\bigstar}$ $\boxed{\underline{\sf{F = ma}}}$

where,

• F = force
• m = mass of the body
• a = acceleration due to gravity

⟶ F = ma

⟶ 20 = 10 × a

⟶ 20/10 = a

⟶ 2 = a

• Acceleration = 2 m/s²

Let the initial velocity (u) = u. Then, the according to the question, the final velocity = 2u

By using the first equation of motion,

⟶ v = u + at

We get,

⟶ 2u = u + 2 × 8

⟶ 2u = u + 16

⟶ 2u - u = 16

⟶ u = 16

Therefore, the initial velocity = 16 m/s.