A uniform force of 30N acts on a mass 2.5kg initially at rest for 5seconds then it withdrawn and a retarding force F now acted on the mass in the direction of the motion to reduce its velocity to 12 m/s.( calculate the momentum of mass before the retarding force starts to cut and the momentum of mass when its velocity is 12m/s if the retarding force acted for 7seconds,calculate its magnitude
Momentum before retarding force
Momentum =impulse =product of mass and velocity
M = Ft = mv
Using force and time
M = ft
= 30N × 5sec
= 150Ns
Momentum of mass when it's velocity is at 12m/s
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A force of 9.0N is applied to a body at rest on a smooth horizontal surface.
If the body has a mass of 18.0kg and it moves in the direction of the force, find the work done in.
a. The first four second. b. The fourth second ? Pls I need answers to this question pls
To calculate the momentum of the mass before the retarding force is applied, we need to use the formula:
Momentum = Mass × Velocity
Given:
Force (F) = 30N
Mass (m) = 2.5kg
Time (t) = 5 seconds
First, we need to calculate the initial velocity (u) using Newton's second law:
F = ma (Force = mass × acceleration)
Since the force is constant, we can solve for acceleration (a) by rearranging the equation:
a = F / m (acceleration = force / mass)
Substituting the values, we have:
a = 30N / 2.5kg = 12 m/s^2
Since the mass is initially at rest, the initial velocity (u) is 0.
Now, we can calculate the momentum before the retarding force starts to act:
Momentum = Mass × Velocity
= 2.5kg × 0
= 0 kg m/s
Next, let's calculate the final momentum when the velocity is 12 m/s after the retarding force is applied for 7 seconds.
Using the same formula, we have:
Momentum = Mass × Velocity
= 2.5kg × 12 m/s
= 30 kg m/s
Therefore, the momentum of the mass before the retarding force is applied is 0 kg m/s, and the momentum of the mass when its velocity is 12 m/s after the retarding force is applied for 7 seconds is 30 kg m/s.