Melinda is pushing a chair along a 5 meter straight path through her living room. She is standing, pushing at the top of the chair with a force of 30 newtons at a 22° angle of depression from the horizontal. (a) Calculate the work done in moving the chair. (b) How could Melinda re-arrange herself to make the energy use more efficient?

An airplane pilot fell to the ground after jumping from an aircraft without his parachute opening. He lands in a snowbank, creating a crater 2.1 m deep, but survived with only minor injuries.  Assuming the pilot’s mass was 68 kg and his terminal velocity was 35 m/s (the velocity at the point he stopped accelerating on his way down), what is: a) the average force exerted on him by the snow in bringing him to rest?  b) the work done by the snow?

A box is supported by a 4.6 N vertical force and carried 2.3 m horizontally across a room at constant speed. Then, the same box is pushed 2.3 m horizontally across a smooth table (smooth enough to ignore friction) by a 4.6 N horizontal force. In which case was more work done on the box by the 4.6 N force? More work was done when the box was pushed across the table. More work was done when the box was carried across the room. The work was the same in each case, since the force and distance were of equal magnitudes in both situations.

Lamar Gant, U.S. powerlifting star, became the first man to deadlift five times his own body weight in 1985. Deadlifting involves raising a loaded barbell from the floor to a position above the head with outstretched arms. Determine the work done by Lamar in deadlifting 300 kg to a height of 0.90 m above the ground.

A crane slowly lifts a 263 - kg crate a vertical distance of H = 13.0 m. mg crane F crane (a) How much work does the crane do on the crate? Enter to 3 significant figures W H 0 33,500 (b) How much work does the gravity do on the crate? Enter to 3 significant figures X√J XVI W gravity (c) What is the total work done on the crate? Enter to 3 significant figures ✓J W total = -33,500

A child on a sled is initially at rest on an icy horizontal surface. The sled is pushed until it reaches a final velocity of 6.05 m/s in a distance of 15.6 m. The coefficient of friction between the ice and runners of the sled is 0.200, and the weight of the child and the sled is 375 N. Find the work done by the force pushing the sled.

A block of mass m = 4.00 kg is pushed a distance d = 2.50 m along a frictionless horizontal table by a constant applied force of magnitude F = 16.0 N directed at an angle θ = 28.0° below the horizontal as shown in the figure below. (a) Determine the work done on the block by the applied force. (b) Determine the work done on the block by the normal force exerted by the table. (c) Determine the work done on the block by the force of gravity. (d) Determine the work done by the net force on the block.

The skateboarder in the figure is coasting down a ramp, and there are three forces acting on her: her weight W (magnitude = 669 N), a frictional force (magnitude = 162N) that opposes her motion, and a normal force FN (magnitude = 625 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 10.6 m. (a) Number 21.0° (a) Mi (b) Number i (c) Number i e-69.0° 8 = 180.0° Units Units Units Weight component FN e-90.0° (b)

A block of mass m = 3.20 kg is pushed a distance d = 5.20 m along a frictionless horizontal table by a constant applied force of magnitude F = 16.0 N directed at an angle 0 = 28.0° below the horizontal as shown in the figure below. (a) Determine the work done on the block by the applied force. (b) Determine the work done on the block by the normal force exerted by the table. (c) Determine the work done on the block by the force of gravity. (d) Determine the work done by the net force on the block.

When 150 joules of work is done on a system byan external force of 15 newtons in 20. seconds,the total energy of that system increases by (1) 1.5 × 10^2 J (3) 3.0 × 10^2 J(2) 2.0 × 10^2 J (4) 2.3 × 10^3 J