Answer:
Work done, W = 0.0219 J
Explanation:
Given that,
Force constant of the spring, k = 290 N/m
Compression in the spring, x = 12.3 mm = 0.0123 m
We need to find the work done to compress a spring. The work done in this way is given by :
W = 0.0219 J
So, the work done by the spring is 0.0219 joules. Hence, this is the required solution.
Answer:
Negative, because the speed is decreasing.
Answer:
a. 120 W
b. 28.8 N
Explanation:
To a good approximate, the only external force that does work on a cyclist moving on level ground is the force of air resistance. Suppose a cyclist is traveling at 15 km/h on level ground. Assume he is using 480 W of metabolic power.
a. Estimate the amount of power he uses for forward motion.
b. How much force must he exert to overcome the force of air resistance?
(a)
He is 25% efficient, therefore the cyclist will be expending 25% of his power to drive the bicycle forward
Power = efficiency X metabolic power
= 0.25 X 480
= 120 W
(b)
power if force times the velocity
P = Fv
convert 15 km/h to m/s
v = 15 kmph = 4.166 m/s
F = P/v
= 120/4.166
= 28.8 N
definition of terms
power is the rate at which work is done
force is that which changes a body's state of rest or uniform motion in a straight line
velocity is the change in displacement per unit time.
The two will fall at the same speed and reach the surface at the same time. This is because the two will experience the same gravitational acceleration on the moon. However, on the earth surface the two will land on the surface of the earth at the same time due to air resistance such that the egg will experience a higher air resistance than the hammer. On, the moon, where there is no noticeable atmosphere there is no air resistance on either object and both fall at the same speed. It is also important to note that their mass doesn't affect their speed.
