91Ó°ÊÓ

Given: $$ \begin{aligned} E_{p} &=93.6 \mathrm{~J} \\ g &=9.80 \mathrm{~m} / \mathrm{s}^{2} \\ m &=2.30 \mathrm{~kg} \\ h &=? \end{aligned} $$

A \(10.0\) -kg mass is dropped from a hot air balloon at a height of \(325 \mathrm{~m}\) above the ground. Find its speed at points \(30 \overline{0} \mathrm{~m}, 20 \overline{0} \mathrm{~m}\), and \(10 \overline{0} \mathrm{~m}\) above the ground and as it hits the ground.

Given: $$ \begin{aligned} W &=55.0 \mathrm{~J} \\ t &=11.0 \mathrm{~s} \\ P &=? \end{aligned} $$

A truck with mass \(95 \overline{0}\) slugs is driven \(55.0 \mathrm{mi} / \mathrm{h}\). (a) What is its velocity in \(\mathrm{ft} / \mathrm{s}\) ? (b) What is its kinetic energy?

The work required to lift a crate is \(31 \overline{0} \mathrm{~J}\). If the crate is lifted in \(25.0 \mathrm{~s}\), what power is developed?

When a \(36 \overline{0} 0\) -lb automobile runs out of gas, it is pushed by its unhappy driver and a friend a quarter of a mile \((0.250 \mathrm{mi})\). To keep the car rolling, they must exert a constant force of \(175 \mathrm{lb}\). (a) How much work do they do? (b) If it takes them \(15.0\) min, how much power do they develop? (c) Expressed in horsepower, how much power do they develop?

Given: $$ \begin{aligned} F &=m a \\ m &=16.0 \mathrm{~kg} \\ a &=9.80 \mathrm{~m} / \mathrm{s}^{2} \\ s &=13.0 \mathrm{~m} \\ W &=? \end{aligned} $$

A bullet with mass \(12.0 \mathrm{~g}\) travels \(415 \mathrm{~m} / \mathrm{s}\). Find its kinetic energy. (Hint: Convert \(12.0 \mathrm{~g}\) to \(\mathrm{kg}\).)

A sandbag is dropped from a hot air balloon at a height of \(125 \mathrm{~m}\) above the ground. Find its velocity as it hits the ground. Disregard air resistance.

A bicycle and rider together have a mass of \(7.40\) slugs. If the kinetic energy is \(742 \mathrm{ft} \mathrm{lb}\), find the velocity.