A boy drops a ball from an observation tower. The ball hits the ground in 5.0 s. What is the ball's velocity at the time of impact?

A. 0 m/s

B. 98 m/s

C. 49 m/s

D. 123 m/s

In the United States when is the length of the day longest

1. The efficiency of a Carnot engine is e=1-Tc/TH, where Tc is a temperature of the cold reservoir and TH is a temperature of the hot reservoir.

Consider the following reaction: a. How much heat is evolved for the production of 1.00 mol of H2O (l) ? b. How much heat is evolved when 4.03 g of hydrogen is reacted with excess oxygen? c.

What will happen if I put my hand in a space vacuum.

In a circus performance, a monkey is strapped to a sled and both are given an initial speed of 2.0 m/s up a 20.0° inclined track. The combined mass of monkey and sled is 24 kg, and the coefficient of kinetic friction between sled and incline is 0.20.

What is the main optical element of a refracting telescope?

Two water manometers are connected to a tank of air. One leg of the manometer is open to 100kPa pressure (absolute) while the other leg is subjected to 90kPa. Find the difference in deflection between both manometers, Delta h_a - Delta h_b.

Most geologists believe that the dinosaurs became extinct 65 million years ago when a large comet or asteroid struck the earth, throwing up so much dust that the sun was blocked out for a period of many months. A.

If you drop a silver dollar off a building and it hits the ground in 10 seconds, how fast was the coin going just before it hit?

What is the weight of an with a mass of 32kg