a body of a mass 500g is moving with a speed 20m/s when brakes are applied it comes to rest in next 0.05s calculate the change in momentum and the average force applied
Answers
Required Answer :
The change in momentum = - 10000 Nm
The average force applied on the body = - 2,00,000 N
Given :
- Mass of a body = 500 g
- Initial velocity of the body = 20 m/s
- Final velocity of the body = 0 m/s [Because it comes to rest.]
- Time = 0.05 seconds
To find :
- Change in momentum
- Average force applied on the body
Formulae to be used :
Formula to calculate the change in momentum :
- Change in momentum = m(v - u)
First equation of motion :
- v = u + at
Formula to calculate the force applied :
- F = ma
where,
- m = mass
- v = Final velocity
- u = Initial velocity
- a = Acceleration
- F = Force
Solution :
Calculating the change in momentum :
Using formula,
- Change in momentum = m(v - u)
Substituting the given values :
⇒ Change in momentum = 500(0 - 20)
⇒ Change in momentum = 500(-20)
⇒ Change in momentum = - 10000
Therefore,
- The change in momentum = - 10000 Nm
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Calculating the average force applied on the body :
Firstly, let's calculate acceleration of the body by using the first equation of motion.
First equation of motion :
- v = u + at
Substituting the given values :
⇒ 0 = 20 + (a)(0.05)
⇒ - 20 = a × 0.05
⇒ - 20/0.05 = a
⇒ - 400 = a
Acceleration of the body = - 400 N
Using formula,
- F = ma
Substituting the given values :
⇒ Force = 500 × - 400
⇒ Force = - 2,00,000
Therefore,
- The average force applied on the body = - 2,00,000 N