A bike travels at 20mph for 5 hours, then 10 mph for 3 hours. What is the average speed?
1 answer:
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Answer:
6.57 m/s
Explanation:
First use Hook's Law to determine the F the compressed spring acts on the mass. Hook's Law F=kx; F=force, k=stiffnes of spring (or spring constant), x=displacement
F=kx; F=180(.3) = 54 N
Next from Newton's second law find the acceleration of the mass.
Newton's .2nd law F=ma; a=F/m ; a=54/.75 = 72m/s²
Now use the kinematic equation for velocity (or speed)
v₂²= v₀² + 2a(x₂-x₀); v₂=final velocity; v₀=initial velocity; a=acceleration; x₂=final displacement; x₀=initial displacment.
v₀=0, since the mass is at rest before we release it
a=72 m/s² (from above)
x₀=0 as the start position already compressed
x₂=0.3m (this puts the spring back to it's natural length)
v₂²= 0 + 2(72)(0.3) = 43.2 m²/s²
v₂= = 6.57 m/s
Answer:
B. Outside the nucleus.
Explanation:
Electrons orbit the nucleus of the atom.
Answer:
Explanation:
The equation for Power is
P = Work/time to do work and the equation for work is
Work = FΔx
We first need to find the amount of work done, then we can find the power it took to do that work.
W = 2000(9.8)(28) so
W = 550,000 N*m
Now we fill that into the power equation:
gives us
P = 18000 Watts. But we need kW, so we divide by 1000 to get
P = 18 kW of power.