Question

a body starts from rest and then covers 30m in 5 seconds. Calculate the increase in the velocity per second.

please solve this question
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Answer 1

Answer:

Since the initial velocity is 30 and the velocity is increasing uniformly by 5 meters every second (acceleration is 5 m/s 22 ) then it will take 30 seconds to reach 180 m/s. That is, the change in velocity from 30 to 180 is 150 and since it takes one second to increase by 5 meters/s, then it will take 150/5= 30 seconds to reach 180 m/s.

Formal approach is by using the motion equation v=u+at, where v is the final velocity (180 m/s), u is the initial velocity (30 m/s), a is the acceleration (5 m/s 22 ) and t is the time it takes to reach the velocity of 180. Plugging these values into the equation and rearranging we get t = (180–30)/5 = 30 seconds.

Answer 2

Given :

• A body starts from rest and then covers 30m in 5 seconds.

To find :

• Increase in velocity per second

Solution :

We have,

• Initial velocity of the body = 0 m/s [Because it starts from rest.]

• Distance = 30 m

• Time = 5 seconds

Here, we will use the third equation of motion to find the acceleration.

Third equation of motion :-

• s = ut + ½ at²

where,

• s denotes the distance/displacement

• u denotes the initial velocity

• a denotes the acceleration

• t denotes the time

Substituting the given values :-

⟶ 30 = (0)(5) + ½ × a × (5)²

⟶ 30 = ½ × 25 × a

⟶ 30 = 25/2 × a

⟶ 30 × 2/25 = a

⟶ 2.4 = a

Therefore, acceleration of the body = 2.4 m/s²