Question

By applying force on a stationary body it attains a velocity of 3.6 km/hr in 10 seconds ! mass is 10kg. Calculate the acceleration and force which applies on a body
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Answer 1

Given that,

• Initial velocity (u) = 0 m/s (As it was at stationary position)
• Final velocity (v) = 3.6 km/h
• Time taken (t) = 10 seconds
• Mass (m) = 10 kg

To calculate,

• Acceleration (a)
• Force (f)

Calculation,

In order to find the acceleration, firstly we need to convert final velocity in m/s.

$\longmapsto\rm { v = 3.6 \; kmh^{-1}}$

$\longmapsto\rm { v = \Bigg ( 3.6 \times \dfrac{5}{18} \Bigg ) \; ms^{-1}}$

$\longmapsto\rm { v = \Bigg ( 0.2 \times 5 \Bigg ) \; ms^{-1}}$

$\longmapsto\bf { v = 1 \; ms^{-1}}$

Now, as we know that,

$\longmapsto\bf { a = \dfrac{v-u}{t} }$

• a denotes acceleration
• v denotes final velocity
• u denotes initial velocity
• t denotes time

$\longmapsto\rm { a = \dfrac{1-0}{10} \; ms^{-2}}$

$\longmapsto\bf { a = 0.1 \; ms^{-2}}$

∴ Acceleration of the body is 0.1 m/s².

Now, we have to calculate the force applied. According to the second law of motion,

$\longmapsto\bf {F = ma }$

• F denotes force
• m denotes mass
• a denotes acceleration

$\longmapsto\rm {F = 10 \; kg \times 0.1 \; ms^{-2} }$

$\longmapsto\rm {F = 1 \; kg.ms^{-2} }$

$\longmapsto\bf {F = 1 \; N }$

∴ Force applied is 1 N.

Final answers :

• Acceleration = 0.1 m/s²
• Force applied = 1 N