The (non-conservative) foree propelling a 1.10 x 10°-kg car up a mountain road does 7.50 x 10 J of work on the car. The car starts from rest at sea level and has a speed of 26.0 m/s at an altitude of 2.20 x 102 m above sea level. Obtain the work done on the car by the combined forces of friction and air resistance, both of which are non-conservative forces.

A shopper in a supermarket pushes a cart with a force of 41 N directed at an angle of 25° below the horizontal. The force is just sufficient to overcome various frictional forces, so the cart moves at constant speed. (a) Find the work done by the shopper as she moves down a 42.0-m length aisle. Your response is within 10% of the correct value. This may be due to roundoff error, or you could have a mistake in your calculation. Carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. J (b) What is the net work done on the cart? Why? This answer has not been graded yet. (c) The shopper goes down the next aisle, pushing horizontally and maintaining the same speed as before. If the work done by frictional forces doesn't change, would the shopper's applied force be larger, smaller, or the same? What about the work done on the cart by the shopper? This answer has not been graded yet.

Suppose the ski patrol lowers a rescue sled and victim, having a total mass of 95.0 kg, down a 54.0° slope at constant speed, as shown in the figure. T 60° 13 13 The coefficient of friction between the sled and the snow is 0.100. (a) How much work is done (in J) by friction as the sled moves 30.0 m along the hill? × J (b) How much work is done (in J) by the rope on the sled in this distance? X J (c) What is the work done (in J) by the gravitational force on the sled? 20

A 996 kg car is travelling at a velocity of 15.4 m/s.  How much work must be done on the car by the brakes to stop the car.  Include the correct sign.  Neglect friction except in the braking system.

You and your bicycle have combined mass 80.0 kg. When you reach the base of a bridge, you are traveling along the road at 5.00 m>s (Fig. ). At the top of the bridge, you have climbed a vertical distance of 5.20 m and slowed to 1.50 m/s. Ignore work done by friction and any inefficiency in the bike or your legs. (a) What is the total work done on you and your bicycle when you go from the base to the top of the bridge? (b) How much work have you done with the force you apply to the pedals?

A 60.0 kg skier with an initial speed of 12.0 m/s coasts up a 2.50 m high rise as shown. The coefficient of friction between her skis and the snow is 0.80. K, V = ? Vi 2.5 m 35° Find the work done by friction as she moves up the slope. (in J) Find her final speed at the top.

A 24.5 kg child pulls a 3.75 kg toboggan up a hill inclined at 25.7° to the horizontal. The vertical height of the hill is 30.3 m. Friction is negligible. (a) Determine how much work the child must do on the toboggan to pull it at a constant velocity up the hill. (b) Now suppose that the hill is inclined at an angle of 19.6° but the vertical height is still 30.3 m. What conclusion can you make?

A 61.8-kg skateboarder starts out with a speed of 1.75 m/s. He does 80.4 J of work on himself by pushing with his feet against the ground. In addition, friction does -221 J of work on him. In both cases, the forces doing the work are non-conservative. The final speed of the skateboarder is 9.19 m/s. (a) Calculate the change (PEF - PEo) in the gravitational potential energy. (b) How much has the vertical height of the skater changed? Give the absolute value. (a) Number (b) Number i Units Units

The skateboarder in the figure is coasting down a ramp, and there are three forces acting on her: her weight W (magnitude = 679 N), a frictional force (magnitude = 144N) that opposes her motion, and a normal force FN (magnitude = 630 N). Determine the net work done (a) by the weight W, (b) by the frictional force 7, and (c) by the normal force FN when she coasts for a distance of 11.1 m. 1 love 22.0° (a) FN 0-68.0° W 0 = 180.0° Weight component FN e=90.0° (b)

A person pulls a 75-kg box 20 m along a horizontal floor by a constant force Fp = 125 N, which acts at a 42 degree angle. The floor is not smooth and exerts a friction force of Ff = 65 N.  Determine the following: The work done by each force acting on the crate (Don’t forget any!) The net work done on the crate