a motor car of mass 200 kg is moving with certain velocity. It is brought to rest by the application of force within a distance of 20 m when the average resistance being offered to it is 500 newton .What was the velocity of motor car ?
Answers
Answer:
Explanation:
m = 200 kg
s = 20 m
F = - 500 N
Final velocity v = 0
Initial velocity u = ?
Acceleration = F/m = -500 N/200 kg = -2.5 m/s2.
We have v2-u2 = 2as
u2 = v2-2as
= 0 -2(-2.5)x 20 m2/s2
= 100 m2/s2.
u = 10 m/s
The velocity of the car is 10m/s
GIVEN
A motor car of mass 200 kg is moving with certain velocity. It is brought to rest by the application of force within a distance of 20 m when the average resistance being offered to it is 500 newton.
TO FIND
The velocity of motor car.
SOLUTION
We can simply solve the above problem as follows;
We will first calculate the retardation of the car.
F = ma
Where,
F = Force exerted.
m = mass of the object
Putting the values in the above formula we get,
500 = 200 × a
a = 500/200 = - 2.5 m/s²
Now,
Since the car has been brought to rest, The final velocity of the car is zero.
Applying third equation of motion
v² - u² = 2as
Where,
v = Final velocity
u = initial velocity
a = Retardation
s = displacement of the body.
Putting the values in the above formula we get,
0 -u² = 2 × -2.5 × 20
-u² = -100
u = √100 = 10 m/s
Hence, The velocity of the car is 10m/s
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