Calculating Power Using Applied Force and Velocity: Quick Homework Question

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The discussion revolves around calculating the power exerted by a force on a block being pulled across a floor. The block has a mass of 100 kg and is pulled at a constant speed of 5.0 m/s with a force of 122 N at an angle of 37 degrees. The correct formula for power is P = Fvcos(θ), where θ is the angle of the applied force. A participant initially miscalculated the speed as 5.7 m/s, leading to an incorrect power result. Upon correcting the speed to 5.0 m/s, the participant realized their error and acknowledged the mistake.
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Homework Statement



A 100kg block is pulled at a constant speed of 5.0 m/s across a horizontal floor by an applied force off 122N directed 37 degrees above the horizontal. What is the rate at which the force does work on the block?

Homework Equations



I know here we will use the instantaneous power formula P=dW/dt or P=Fvcos

The Attempt at a Solution



well i drew the FBD and started plugging in numbers in my formula, its just I am not sure where the Mass falls into place here I know the answer is 4.9x10^{}2 watts but not sure where to go from here thanks
 
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In this problem mass is not needed.
 
well my answer just doesn't match up with the answer my teacher gave us and i don't know why... i did 122*5.7sin(37) and came up with 418.5W or 4.2X10^2 W
 
nelly42688 said:
well my answer just doesn't match up with the answer my teacher gave us and i don't know why... i did 122*5.7sin(37) and came up with 418.5W or 4.2X10^2 W
Your calculation is wrong.
122*5*cos(37) = ?
 
wow! the whole time i was using 5.7m/s instead of 5m/s careless mistake sorry to waste your time
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
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