physics-work and energy!
if On a road, a scooterist applies brakes to slow down from a speed of 36 km/h to 18 km/h. Find the work done by the brakes, assuming the mass of the empty scooter to be 86 kg and that of the person equal to 64 kg.

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Solution

Work done by brakes = Change in kinetic energy of the scooter

,W = 1/2mv₁ ² - 1/2mv₂ ²

or W = (1/2).m.[v₁ ² - v₂ ²]

here,

m = 86kg + 64kg = 150kg

v₁ = 36km/hr = 10m/s

v₂ = 18km/hr = 5m/s

so,

W = (1/2)x150x[10² - 5²]

thus, we get

W = 5625 J

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A scooter is moving with an initial velocity of 90km per hour and it takes 10s to stop it,better the brakes are applied. Calculate the force exerted by the brakes on the scooter, if it's mass along with the rider is 200kg. What would be the force if the mass is halved?

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physics-work and energy!if On a road, a scooterist applies brakes to slow down from a speed of 36 km/h to 18 km/h. Find the work done by the brakes, assuming the mass of the empty scooter to be 86 kg and that of the person equal to 64 kg.

Work done by brakes = Change in kinetic energy of the scooter ,W = 1/2mv1 2 - 1/2mv2 2 or W = (1/2).m.[v1 2 - v2 2] here, m = 86kg + 64kg = 150kg v1 = 36km/hr = 10m/s v2 = 18km/hr = 5m/s so, W = (1/2)x150x[102 - 52] thus, we get W = 5625 J

physics-work and energy!
if On a road, a scooterist applies brakes to slow down from a speed of 36 km/h to 18 km/h. Find the work done by the brakes, assuming the mass of the empty scooter to be 86 kg and that of the person equal to 64 kg.

Work done by brakes = Change in kinetic energy of the scooter

,W = 1/2mv₁ ² - 1/2mv₂ ²

or W = (1/2).m.[v₁ ² - v₂ ²]

here,

m = 86kg + 64kg = 150kg

v₁ = 36km/hr = 10m/s

v₂ = 18km/hr = 5m/s

so,

W = (1/2)x150x[10² - 5²]

thus, we get

W = 5625 J