Consider a monkey wrench released at rest at the far edge of the solar system. Suppose that it drops to Earth by virtue of only Earth gravity. It will strike Earth's surface with a speed of about
A)10 m/s.
B)8 km/s.
C)11.2 km/s.
D)the speed of light.

Question

Quizplus · Accepted Answer

The final velocity of the monkey wrench can be calculated with the formula v^2 = u^2 + 2as, where u=0 (since it was released from rest), a=g (the acceleration due to Earth's gravity), and s is the distance it falls (which we will approximate as the distance from the edge of the solar system to Earth's surface, or about 150 billion meters). Plugging in these values, we get v^2 = 2(9.81 m/s^2)(1.5 x 10^11 m) = 2.942 x 10^12 m^2/s^2. Taking the square root of this gives us v = 1.716 x 10^6 m/s, which is equivalent to 11.2 km/s (rounded to two significant figures). Therefore, choice (C) is the correct answer.

Consider a Monkey Wrench Released at Rest at the Far