Question

A car of mass 800kg, moving at 54kmh⁻¹ is brought to rest over a distance of 15m. Find the retarding force developed by the brakes of the car.​

Answer 1

Answer:

here is ur answer.

Explanation:

Answer 2

Given :

• Mass of car, m = 800kg
• Initial velocity of car, u = 54kmh⁻¹ = 15ms⁻¹
• Final velocity of car, v = 0
• Distance covered, s = 15m

Need to find :

• Retarding force, F

Solution :

★ Firstly, we will calculate the acceleration of car using the third equation of motion,

• v² - u² = 2as

where,

• v is the final velocity, u is the initial velocity, a is the acceleration and s is the distance covered. Now, comparing,

→ (0)² - (15)² = 2a(15)

→ 30a = -225

→ a = -225/30

→ a = -7.5ms⁻²

• Hence, the acceleration is -7.5ms⁻²

★ Now, as we know that,

→ F = ma

→ F = 800 × (-7.5)

→ F = -6000N

The negative sign shows retardation.

• Therefore, the retarding force developed by the brakes of the car is -6000N