Question

A truck of mass 8 metric tonnes starts from rest rolls down a hill with constant acceleration. It travels a distance of 400 m in 20s. The force acting on it is

Answer 1

Answer:

16000 N

Explanation:

As per the provided information in the given question, we have :

• Mass of truck (m) = 8 metric tonnes → 8000 kg
• Distance travelled (s) = 400 m
• Time taken (t) = 20 s
• Initial velocity (u) = 0 m/s [From rest]

We've been asked to calculate force.

In order to calculate force, firstly we need to calculate acceleration. In order to calculate acceleration, we'll apply the second equation of motion.

$\qquad \qquad \Bigg [\sf s = ut + \dfrac{1}{2}at^2 \Bigg ]$

• s denotes distance
• a denotes acceleration
• t denotes time
• u denotes initial velocity

Substitute the values as per the formula above.

$\implies\rm{ 400 = 0(20) + \dfrac{1}{2} \times a \times (20)^2}$

$\implies\rm{ 400 = \dfrac{1}{2} \times a \times 400}$

$\implies\rm{ 400 = 200a}$

$\implies\rm{ \cancel{\dfrac{400}{200}} = a}$

$\implies \boxed{\rm{ 2 \; ms^{-2} = a}}$

Now, as we know that Force is the product of mass and acceleration. Its SI unit is Newton and it's a vector quantity.

$\qquad \qquad \Bigg [\sf F = ma \Bigg ]$

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

Substitute the values.

$\implies\rm{ F= 8000 \;kg\times 2 \; ms^{-2} }$

$\implies \underline{\boxed{\bf{F = 16000 \; N}}}$

Therefore, force acting on it is 16000 N.

$\rule{200}2$