A 1000-kg car is moving at 40.0 km/hr when the driver slams on the brakes and skids to a stop (with locked brakes) over a distan
1 answer:
Answer:
skid distance = 180 m
Explanation:
given,
mass of the car = 1000 Kg
speed of the car = 40 Km/hr
distance to stop = 20 m
if speed is now = 120 Km/he
distance to stop = ?
from given question we can state that,
Work done by the friction is equal to the change in kinetic energy of the car.
............(1)
And we also know that work is directly proportional to displacement
W = F × x...........................(2)
from the equation (1) and (2)
x ∝ v²
now,
here velocity is increased from 40 km/h to 120 km/h means velocity is increase 3 times
so displacement will be equal to 3² or 9 times
hence, skid distance will be equal to 9 x 20 = 180 m
skid distance = 180 m
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Height from which ball is dropped , h = 40 m .
Acceleration due to gravity , g= 10 m/s² .
Initial velocity , u = 0 m/s .
To Find :
Velocity when ball covered 20 m and velocity when it hit the ground .
Solution :
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By equation of motion :
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