Q. 3. An object of mass 'm' is allowed to fall freely from a point A as shown in the figure. Calculate the total mechanical energy of object at: (i) Point A (ii) Point B (iii) State the law which is verified by your calculations. [ICSE 2009] A y B.

A car engine produces a constant power of P = 341 hp. The car and motor have a combined mass of m = 1830 kg. 1.) The car starts from rest, after t=5 seconds, what is the cars speed, you may assume no energy is required to spin the tires. 2.) Assume a dragster of mass m=1000kg can accelerate to cover  450 m and accelerate in 7.2 s from a dead stop, how much horsepower is the engine producing, assuming acceleration is constant?

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1. A roller-coaster car with a mass of 1200 kg starts at rest from a point 20 m above the ground. At point B, it is 9 m above the ground. [Express your answers in kilojoules (kJ).] a. What is the initial potential energy of the car? b. What is the potential energy at point B? c. If the initial kinetic energy was zero and the work done against friction between the starting point and point B is 40 000 J (40 kJ), what is the kinetic energy of the car at point B 2. The time required for one complete cycle of a mass oscillating at the end of a spring is 0.80 s. What is the frequency of oscillation?

1. A certain car can accelerate from rest to the speed v in T seconds. If the power output of the car remains constant, (a) how long does it take for the car to accelerate from v to 2v? (b) How fast is the car moving at 2T seconds after starting? Explain and draws.

2. A 5.2-kg box slides a distance of 16.0-m. If the coefficient of kinetic friction is 0.30, what is the work done by the frictio" 6 d x244.64 J ✓cci 6 ccilo 16 cci16 ceiz

1. A 23.0 kg child is playing on a swing with a length of 2.5 m. If the swing starts from rest and makes an angle of 40.0◦ with the vertical at the top of the swing, a) determine the child’s speed at the bottom of the swing neglecting friction. b) If the swing has a speed of 2.8 m/s at the bottom, determine the work done by friction during the downswing and, bonus) assuming the force of friction is constant, determine the maximum angle the swing attains on the upswing after passing through the bottom. Hint: Use the approximation that cos θ ≈ 1 − 1 2 θ 2 for angles given in radians.

Suppose a 385 g kookaburra (a large kingfisher bird) picks up a 70 g snake and raises it 2.4 m from the ground to a branch. (a) How much work (in J) did the bird do on the snake? (b) How much work (in J) did it do to raise its own center of mass to the branch? Additional Materials O Reading