Ice-skater slides toward a sled sitting on the ice and hits it. The skater exerts a 12.6 N force on the sled at an angle of 15.3° below the horizontal. The sled then moves 15.4 m forward. How much work did the skater do on the sled? Assume friction is negligible.

Knowns Unknown

F = d = W = ?

θ =

Solve for the Unknown

a. Write the equation for work
b. Insert known quantities

Humidity is to blame for that muggy, steamy feeling you experience on some hot summer days. what gas in the atmosphere causes humidity? a) oxygen b) hydrogen c) nitrogen d) water vapor

According to newton’s law of universal gravitation, which statements are true? as we move to higher altitudes, the force of gravity on us decreases. as we move to higher altitudes, the force of gravity on us increases. as we gain mass, the force of gravity on us decreases. as we gain mass, the force of gravity on us increases. as we move faster, the force of gravity on us increases.

A47.2 g block of copper whose temperature is 480 k is placed in an insulating box with a 91.8 g block of lead whose temperature is 200 k. (a) what is the equilibrium temperature of the two-block system? (b) what is the change in the internal energy of the two-block system between the initial state and the equilibrium state? (c) what is the change in the entropy of the two-block system? the heat capacities of copper and lead are 386 j/kg·k and 128 j/kg·k, respectively.