1, While passing between Earth and the Moon, a spacecraft is momentarily located on the line connecting the centers of the two bodies and is at a distance ofd=137km from a radio antenna on the surface of Earth. The distance from the antenna to the moon is denoted byd_m.

Recall that the speed of light is 3.0 10⁸m/s. How long, in seconds, does it take for a signal from the spacecraft to arrive at the antenna on Earth?

t₁=

2, In a biathalon race you first ride a bicycle at an average speed of20.4mi/h for22.5miles, then you must run for another5.5miles.

With what average speed, in miles per hour, must you run if your average speed for the entire race is to be14.5mi/h?

v_2,ave=

3, At timet₀= 0 a car starts moving southward from rest. It continues moving in the same direction and by timet_f=118s has covered a distanced=689m. Take northward as the positivex-direction. Refer to the figure

What is the car's average speed during this period, in meters per second?

s=

4, At the equator, the radius of the Earth is approximately 6370 km. A jet flies at a very low altitude at a constant speed ofv=250m/s. Upon landing, the jet can produce an average deceleration ofa=22m/s².

How long will it take the jet, in seconds, to circle the Earth at the equator?

t=

5, A student launches a small rocket which starts from rest at ground level. At a height ofh=1.85km the rocket reaches a speed ofv_f=388m/s. At that height the rocket runs out of fuel, so there is no longer any thrust propelling it. Take the positive direction to be upward in this problem.

Assuming constant acceleration, what is the rocket's acceleration, in meters per second squared, during the period from its launch until it runs out of fuel?

a₁=