Question

A body starting from rest moves with the constant acceleration of 2 m/s2. The speed of the body after 4 s is​

Answer 1

Required Answer :

The speed of the body after 4 seconds = 8 m/s

Given :

• Initial velocity of the body = 0 m/s [The initial velocity of the body because it was initially at rest.]
• Acceleration of the body = 2 m/s²
• Time = 4 seconds

To find :

• Speed of the body after 4 seconds (Final velocity)

Solution :

Here, we need to calculate the speed of the body and we are given the initial velocity, acceleration and the time of the body. So, to find the speed we will use the first equation of motion.

First equation of motion :

• v = u + at

where,

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

we have,

• u = 0 m/s
• a = 2 m/s²
• t = 4 seconds

Substituting the given values :

⇒ v = 0 + (2)(4)

⇒ v = 2 × 4

⇒ v = 8

The final velocity of the body = 8 m/s

Therefore, the speed of the body after 4 seconds = 8 m/s

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Know more :

Second equation of motion :

• s = ut + ½ at²

Third equation of motion :

• v² - u² = 2as

where,

• s denotes the distance travelled
• u denotes the initial velocity
• a denotes the acceleration
• t denotes the time
• v denotes the final velocity