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cacaluch

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**Homework..urgent help**

1.) If a woman lifts a 19.2 kg bucket from a well and does 6.83 kJ of work, how deep is the well? Assume that the speed of the bucket remains constant as it is lifted.

2.) A constant force of 38.3 N, directed at 26.9° from horizontal, pulls a mass of 12.1 kg horizontally a distance of 2.77 m. Calculate the work done by the force.

3.) A block of mass 2.30 kg is pushed 2.13 m along a frictionless horizontal table by a constant 18.2 N force directed 27.6o below the horizontal. Determine the work done by the applied force.

Determine the magnitude of the normal force exerted by the table.

Determine the magnitude of the force of gravity.

Determine the net force on the block.

4.) Two carts are moving along an air track at the same speed, but in opposite directions. Cart A has a mass of 250 g. Cart B has a mass of 750 g. The kinetic energy of cart A is 9.0 J.

What is the kinetic energy of cart B?

What is the speed of cart A?

5.) A 0.520 kg particle has a speed of 1.60 m/s at point A and kinetic energy of 7.54 J at point B. What is its kinetic energy at A?

What is its speed at point B?

What is the total work done on the particle as it moves from A to B?

6.) Calculate the change in potential energy of a 90.4 kg man when he takes an elevator from the first floor to 26th floor, if the distance between floors is 4.29 m.

7.) A 0.474 kg bead slides on a curved wire, starting from rest at point A as seen in the Figure below.

Assume h1 = 5.27 m and h2 = 1.12 m. If the wire is frictionless, find the speed of the bead at B.

If the wire is frictionless, find the speed of the bead at C.

8.)

The launching mechanism of a toy gun consists of a spring of unknown spring constant, as shown in the figure below.

If the spring is compressed a distance of 0.105 m and the gun fired vertically as shown, the gun can launch a 24.3g projectile from rest to a maximum height of 19.2 m above the starting point of the projectile. Neglecting all resistive forces, determine the spring constant.

Determine the speed of the projectile as it moves through the equilibrium position of the spring (where x = 0) (as shown in (b)).

9.)

The ball launcher in a pinball machine has a spring that has a force constant of 1.15 N/cm (see the figure below).

The surface on which the ball moves is inclined = 17.3o with respect to the horizontal. If the spring is initially compressed 5.53 cm, find the launching speed of a 0.130 kg ball when the plunger is released. Friction and the mass of the plunger are negligible.

10.)

A 30.0 kg child slides down a long slide in a playground. She starts from rest at a height h1 of 21.00 m. When she is partway down the slide, at a height h2 of 10.00 m, she is moving at a speed of 7.30 m/s. Calculate the mechanical energy lost due to friction (as heat, etc.).

11.)

What is the power when you do 140 J of work in 6 s?

12.) A car is stopped for a traffic signal. When the light turns green, the car accelerates, increasing its speed from 0 to 5.63 m/s in 0.872 s. What is the magnitude of the linear impulse experienced by a 69.3 kg passenger in the car during this time?

What is the average force experienced by the passenger?

13.) A 95.0 kg diver falls from rest into a swimming pool from a height of 4.70 m. It takes 1.60 s for the diver to stop after entering the water. Find the magnitude of the average force exerted on the diver during that time.

14.) A linebacker of mass 119.0 kg sacks a quarterback of mass 93.0 kg. Just after they collide, they are momentarily stuck together, and both are moving at a speed of 3.00 m/s. If the quarterback was at rest just before he was sacked, how fast was the linebacker moving just before the collision?

15.) High speed stroboscopic photographs show that the head of a 180 g golf club is traveling at 51.2 m/s just before it strikes a 45.2g golf ball at rest on a tee. After the collision, the club head travels (in the same direction) at 38.9 m/s. Find the speed of the golf ball just after impact.

16.) An 6.61g bullet is fired into a 230g block that is initially at rest at the edge of a table of h = 1.12 m height (see the figure below).

The bullet remains in the block, and after the impact the block lands d = 1.89 m from the bottom of the table. Determine the initial speed of the bullet.

17.) A bullet of mass m= 0.0240 kg is fired along an incline and imbeds itself quickly into a block of wood of mass M= 1.45 kg. The block and bullet then slide up the incline, assumed frictionless, and rise a height H= 1.25 m before stopping. Calculate the speed of the bullet just before it hits the wood. Note. The block is kept from sliding down the incline initially by as small peg (not shown).