At a post office, a package of mass 1.3 kg is pushed down a slanted chute with an initial speed of 1.8 m/s. The upper end of the chute if 4.0 m above the floor. When it reaches the floor, the package has a speed of 0.9 m/s. Determine the energy lost through air resistance and friction with the chute.

In the figure, a constant external force P = 300 N is applied to a 20.0 kg box, which is on a rough horizontal surface. While the force pushes the box a distance of 8.00 m, the speed changes from 0.500 m/s to 2.60 m/s. The work done by friction during this process is closest to P 30° 20 kg -8.0 m O A. +2209 J ОВ.-1948 J OC.-2013 J O D.+1948 J O E. +2013 J

A 2-kg block travels from the top of a plane inclined 25° with the horizontal compressing a spring at the bottom of the incline with an initial speed of 0.65 m/s. Due to the motion of the block, the spring was compressed by 0.2 meters. The spring has a k of 100 N/m and the coefficient of friction between the block and the incline is 0.40. What is the initial kinetic energy of the block? O -0.8) O 041 O -0.4)

10. A 0.58-kg ball is thrown vertically upward with an initial speed of 13.5 m/s. What is the potential energy of the ball when it has travelled three-quarters of the distance to its maximum height? (Use reference point of measurements of the heights) 50 ssr sf60 ss sf60 s 60 091S

The force exerted by a diving board is conservative, provided the internal friction is negligible. Assuming friction is negligible, describe changes in the potential energy of a diving board as a swimmer drives from it, starting just before the swimmer steps on the board until just after his feet leave it.

In the figure, a 4.2 kg block is accelerated from rest by a compressed spring of spring constant 650 N/m. The block leaves the spring at the spring's relaxed length and then travels over a horizontal floor with a coefficient of kinetic friction k = 0.229. The frictional force stops the block in distance D = 8.3 m. What are (a) the increase in the thermal energy of the block-floor system, (b) the maximum kinetic energy of the block, and (c) the original compression distance of the spring? - No friction (a) Number i Units (b) Number Units (c) Number i Units > > >

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A 7.80-g bullet moving at 470 m/s penetrates a tree trunk to a depth of 6.50 cm. (a) Use work and energy considerations to find the average frictional force that stops the bullet. (b) Assuming the friction force is constant, determine how much time elapses between the moment the bullet enters the tree and the moment in stops moving.

Part III: Open Response Springs and ropes are ideal. g=10m/s U(x) (joules) 2 1 3 4 5 6. 7 x (meters) The above graph shows the potential energy U(x) of a 0.1 kg object as a function of its position x. Suppose the object has a constant total energy of 4.0 joules, as shown by the dashed line on the graph. 7. (a) Label all points of stable equilibrium and unstable equilibrium on the graph. (b) What happens to the speed of the object as it moves from 2m to 4m? (c) Can the object reach the position x = 0.5 m? Explain. (d) What is the velocity and the acceleration of the object at x = 6.0 m?

A 7.80-g bullet moving at 650 m/s penetrates a tree trunk to a depth of 5.80 cm. (a) Use work and energy considerations to find the average frictional force that stops the bullet. (Enter the magnitude.) N (b) Assuming the frictional force is constant, determine how much time elapses between the moment the bullet enters the tree and the moment it stops moving.