The theory of global warming states that the average temperature of the earth has been increasing over time.
a. allow the measurement of the earth’s temperatures at the poles.
b. reveal how the earth’s temperature has fluctuated in the past.
c. reveal how the earth’s temperature varies from location to location.
d. allow the measurement of the earth’s temperature with greater precision.

Asled is being held at rest on a slope that makes an angle θ with the horizontal. after the sled is released, it slidesa distance d1 down the slope and then covers the distance d2 alongthe horizontal terrain before stopping. find the coefficient ofkinetic friction μk between the sled and the ground, assumingthat it is constant throughout the trip. find the coefficient of kinetic frictionμk. express your answer in terms of someor all of the variables d1, d2, and θ.