Classical Mechanics Answers

Dania is dragging a 110 kg trunk across a rough floor at a constant velocity of 5.6 m/s [E] with a horizontal force of 380 N [E].

1. Calculate the coefficient of kinetic friction between the trunk and floor.
2. Sonya decides to help by pulling on the trunk with a force of 150 N [Up].  Will Sonya be helping Dania?  Explain
3. Calculate the force Dania needs to pull at now in order to keep a constant speed.
4. Another student (not as nice as Sonya) sits on the trunk.  They have a mass of 55 kg.  What force does Dania need to pull at now for a constant speed?

Shaurya is going tobogganing.  Shaurya and the toboggan have a combined mass of 95 kg.  Once Shaurya reaches the bottom of the hill, he is travelling at 6.5 m/s.  After travelling for 14.6 m over level ground, he comes to a stop.  What is the coefficient of kinetic friction between Shaurya’s toboggan and the snow

1. A hockey puck of mass 0.245 kg leaves a hockey stick at a speed of 29 m/s.  The coefficient of kinetic friction between the ice and puck is 0.080.

a. What is the acceleration of the puck once it leaves the stick?

b. How long will it take for the puck to stop?

c. Repeat part (a) for a puck of twice the mass.

A loaded dogsled has mass of 400 kg and is being pulled across a horizonal, packed snow surface at a velocity of 4.0 m/s (N). Suddenly the harness separates from the sled. If the coefficient of kinetic friction for the sled on the snow is 0.0500, how far will the sled coast before stopping?

A stone is found to weigh 6.2 in air, 4.5 in water, and 5.3 N in an unknown liquid. Find a.) the density of the stone and the unknown liquid, b.) the buoyant force of the liquid on the stone, c.) the buoyant force of water on the stone, and d) the volume of the stone.

An aluminum ball of mass 54.0 g and density 2.70 g/cm³ is placed in a beaker filled with water. a.) What is the volume of the ball? b.) What is the volume of water that will spill out of the beaker? c.) What is the buoyant force of the water on the ball?

Using the information from question #561a above:

b) What is his weight on the moon? _____ newtons

Using the information from question #561a above:

b) What is his weight on the moon? _____ newtons