Mass is a measure of how much matter there is within an object, typically given in grams. Mass is not affected by gravity, so a given object would have the same mass on earth as in outer space. Density is the amount of mass in an object per a certain amount of volume
Answer:
100Kg.m/s
Explanation:
From the question, we obtained the following information:
M= Mass = 25kg
V = Velocity = 4m/s
Momentum =?
Momentum = MV = 25x4= 100Kg.m/s
Complete Question
A flywheel in a motor is spinning at 510 rpm when a power failure suddenly occurs. The flywheel has mass 40.0 kg and diameter 75.0 cm . The power is off for 40.0 s , and during this time the flywheel slows down uniformly due to friction in its axle bearings. During the time the power is off, the flywheel makes 210 complete revolutions. At what rate is the flywheel spinning when the power comes back on(in rpm)? How long after the beginning of the power failure would it have taken the flywheel to stop if the power had not come back on, and how many revolutions would the wheel have made during this time?
Answer:

Explanation:
From the question we are told that:
Angular velocity 
Mass 
Diameter d 
Off Time 
Oscillation at Power off 
Generally the equation for Angular displacement is mathematically given by




Generally the equation for Time to come to rest is mathematically given by



Therefore Angular displacement is


Please be more specific because they all transmit signals but the most common one is the radio wave because it transmits cellphone , televition and radio signals
Almost true but not quite.
That would give you the negative of the actual acceleration.
It should be the other way around:
(final v) minus (initial v), then divide by time.