Mathematics: Which requires that the brakes of a car do the most amount of work? 1. none of these 2. slowing down from 50 km/h to rest 3. both require the same work 4. slowing down from 100 km/h to 50 km/h 5. not enough information is given

GCD of 16 and 6 is 2;Step-by-step explanation:...

Which requires that the brakes of a car do the

bobbycisar1205

18.01.2022

4. Slowing down from 100 km/h to 50 km/h

Step-by-step explanation:

The work done by car is given as the change in the kinetic energy of the car. Mathematically,

W = ΔK

where

W = work done by the brakes.

ΔK = Change in kinetic energy.

Kinetic Energy is given as:

$K = \frac{1}{2}mv^{2}$

Case 1: The car goes from 50 km/h to 0 km/h

ΔK = $K_{f} - K_{i}$

ΔK = $(\frac{1}{2}*50^{2}*m) - (\frac{1}{2}*0^{2}*m)$

ΔK = 1250m J

∴ W = 1250m J

Case 2: The car goes from 100 km/h to 50 km/h

ΔK = $K_{f} - K_{i}$

ΔK = $(\frac{1}{2}*100^{2}*m) - (\frac{1}{2}*50^{2}*m)$

ΔK = 5000m - 1250m

ΔK = 3750m J

∴ W = 3750m J

Note: Mass of the car is constant.

Hence, slowing down from 100 km/h to 50 km/h requires the brakes to do more work, precisely 3 times more work (3750m/1250m = 3)

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