Is it reasonable that a $30$-kg child could run fast enough to have $100$ J of kinetic energy?

A factory worker pushes a $30.0$-kg crate a distance of $4.5$ m along a level floor at constant velocity by pushing horizontally on it. The coefficient of kinetic friction between the crate and the floor is $0.25$. What is the total work done on the crate?

A $1.50$-kg book is sliding along a rough horizontal surface. At point $A$ it is moving at $3.21$ m/s, and at point $B$ it has slowed to $1.25$ m/s. How much work was done on the book between $A$ and $B$?

A surgeon is using material from a donated heart to repair a patient's damaged aorta and needs to know the elastic characteristics of this aortal material. Tests performed on a $16.0$-cm strip of the donated aorta reveal that it stretches $3.75$ cm when a $1.50$-N pull is exerted on it. What is the force constant of this strip of aortal material?

You throw a $3.00$-N rock vertically into the air from ground level. You observe that when it is $15.0$ m above the ground, it is traveling at $25.0$ m/s upward. Use the work–energy theorem to find its maximum height.

Two tugboats pull a disabled supertanker. Each tug exerts a constant force of $1.80\times {10}^6$ N, one $14°$ west of north and the other $14°$ east of north, as they pull the tanker $0.75$ km toward the north. What is the total work they do on the supertanker?

You throw a $3.00$-N rock vertically into the air from ground level. You observe that when it is $15.0$ m above the ground, it is traveling at $25.0$ m/s upward. Use the work–energy theorem to find the rock's speed just as it left the ground.