Question

A truck starts from rest and rolls down a hill with constant acceleration. It travels a distance of 400 m in 20 seconds. Find its acceleration.​

Answer 1

✬ Acceleration = 2 m/s² ✬

Explanation:

Given:

• A truck starts from rest.
• Distance travelled by truck is 400m.
• Time taken is 20 seconds.

To Find:

• What is the acceleration of truck ?

Formula to be used:

• S = ut + 1/2at²

Solution: Here we have

• Initial velocity (u) = 0
• Distance (s) = 400 m
• Time (t) = 20 seconds
• Acceleration (a) = ?

Putting the values on formula

$\implies{\rm }$ S = ut + 1/2at²

$\implies{\rm }$ 400 = 0 × 20 + 1/2 × a × (20)²

$\implies{\rm }$ 400 = a/2 × 400

$\implies{\rm }$ 400 = a × 200

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

$\implies{\rm }$ 2 m/s² = a

Hence, the acceleration of truck is 2 m/s².

Two other laws of motion are

• v² = u² + 2as
• v = u + at

• The rate of change of velocity is called acceleration. It is denoted by a.

• The velocity at which motion starts is termed as initial velocity. It is denote by u.

Answer 2

Answer:

• The acceleration of truck is 2 m/s².

Explanation:

Given that,

• Distance (s) = 400 m
• Time (t) = 20 sec
• Initial velocity (u) = 0 m/s

❤Applying 2nd equation of motion,❤

s = ut + 1/2 × at²

[ Putting values ]

↪ 400 = 0 × 20 + 1/2 × a × 20²

↪ 400 = 1/2 × a × 400

↪ 400 = 200a

↪ a = 400/200

↪ a = 2 m/s²

$\red\bigstar$ Acceleration = 2 m/s² $\green\bigstar$