Question

A car starts from rest and attains a velocity of 10 metre per second in 40

seconds .the driver applies brakes and slows down the car to 5 metre per

second in 10 seconds. Find the acceleration of the car in both the cases?​

Answer 1

‹«« In 1st Case »»›

Given :-

• Initial Velocity (u) = 0 m/s ( as it is at rest)
• Final Velocity (v) = 10 m/s
• Time (t) = 40 second

To Find :-

• Acceleration = ?

Solution :-

Formula Used :-

• v = u + at

Substituting Values

⟹ 10 = 0 + a × 40

⟹ 10 = 0 + 40a

⟹ 10 - 0 = 40a

⟹ 10 = 40a

⟹ 40a = 10

⟹ a = 10/40

⟹ a =0.25

Thus, acceleration is 0.25 m/s²

‹«« In 2nd Case »»›

Given :-

• Initial Velocity (u) = 10 m/s
• Final Velocity (v) = 5 m/s
• Time (t) = 10 second

To Find :-

• Acceleration = ?

Solution :-

Formula Used :-

• v = u + at

Substituting Values

⟹ 5 = 10 + a × 10

⟹ 5 = 10 + 10a

⟹ 5 - 10 = 10a

⟹ - 5 = 10a

⟹ 10a = -5

⟹ a = -5/10

⟹ a = -1/2

⟹ a = -0.5

Thus, here acceleration is -0.5 m/s²