Question

a car starts from rest and moves with a uniform accelaretion for 2s after that it starts to moves with the uniform decelaeation of 4m/s^2 the accelatation of the body if it takes 3s for the car to stop is​

Answer 1

Answer

• The acceleration of the body is 6 m/s²

Explanation

Given

• A car starts from rest
• It has an acceleration for 2 seconds
• Then it decelerates at a rate of 4 m/s²
• It takes 3 seconds for the car to stop

To Find

• The acceleration of the car

Solution

• First find the velocity of the body during the time of deceleration so during this period the final velocity of case 1 will be the initial velocity. So the. compare these two to get the answer!!

✭ In Case 2

→ v = u+at [First equation of motion]

• v = Final velocity = 0 m/s [The car stops]
• u = ?
• a = Acceleration = -4 m/s²
• t = Time = 3 sec

→ 0 = u + -4×3

→ -u = -12

→ u = 12 m/s

✭ In Case 1

→ v = u+at

• v = 12 m/s
• u = 0 m/s [Starts from rest]
• a = ?
• t = 2 sec

→ 12 = 0 + a×2

→ 12 = 2a

→ 12/2 = a

→ Acceleration = 6 m/s²