A sedan car of mass 200kg is moving with a certain velocity . It is brought to rest by the application of brakes, within a distance of 20 m when the average resistance being offered to it is 500 N. What was the velocity of motor car
Answers
In the above Question , the following information is given -
A sedan car of mass 200kg is moving with a certain velocity .
It is brought to rest by the application of brakes, within a distance of 20 m .
The force applied on it is 500 N
To find -
Average velocity of the car.
Solution -
We know that from Newtonian Motion -
F = m a
Here -
F = 500 N
M = 200 kg
a = ?
=> 500 = 200 a
=> a = ( 5 / 2 ) = 2.5 metres per second² .
Now , this it's retardation .
According to the third law of motion -
V² = U² + 2as
V = Final Velocity = 0
U = Initial Velocity
A = acceleration = 2.5
S = displacement = 20 m
Substituting these values -
0 = U² - 2 × 2.5 × 20
=> U² = 100 m / s
=> U = 10 m / s or -10 m / s
This is the required answer.
Note that U can be positive as well as negative here , as this is velocity .
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YOUR QUESTION :
A sedan car of mass 200kg is moving with a certain velocity . It is brought to rest by the application of brakes, within a distance of 20 m when the average resistance being offered to it is 500 N. What was the velocity of motor car?
YOUR ANSWER :
Given :
- A sedan car of mass 200kg is moving with a certain velocity.
- A distance of 20 m when the average resistance being offered to it is 500N.
To find :
- Velocity of motor car.
Solution :
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.