Systems of Particles

1. A 1500kg automobile starts from rest on a horizontal road and gains speed of 72km/h in 30 s. a) what is the average power required of the car at the end of the 30 s? b) what is the average power required of the car during the 30 s interval? c) what is the instantaneous power at the end of the 30 s interval, assuming ...continues

Momentum and Impulse inquiry

While being thrown, a net force of 132 N acts on a baseball (mass = 140 g) for a period of 4.5 X 10^-2 seconds. The balls initial velocity is zero before leaving the pitchers hand. When the batter hits the ball, a net force of 1320 N, opposite the direciton of the balls initial motion, acts on the ball for 9 X 10^-3 seconds du ...continues

Vector subtraction

The magnitudes of the vectors A and B shown in Gigure 2.24 are A = 3 m and B = 2 m. Find graphically: (a) A+B; and (b) A-B? I got the addition but the subtraction came out wrong, can anyone tell me why? I've attached a graph of the original vectors and then my solution.

Angle between two vectors

The vector A has a magnitude of 6m and vector B has magnitude of 4 m. That is the angle between them if the magnitude of the resultant is (a) 3m (b) 8m? Let vector A lie along the x-axis. Do each part graphically and by components. (I tried to use a trial and error approach but I still got this one wrong)

Displacement

In a yacht race the boats sail around three buoys. What is the displacement from the last buoy to the starting point? (a) unit vector notation (b) magnitude and direction? (The answer they give is -2.47 i-.35j and 2.49 at 8 degrees sounth of West. I have no idea where they get there. I've attached my solution, which came out wr ...continues

Displacement

A ship sails FROM a point oat a distance of 4km and a breaking of 40 degrees north of east relative to a lighthouse to a point 6km form the lighthouse at 60 dgrees north of west. What is the displacement? and What is the least distance between them? I figured out the displacment, but how do you find the least distance between t ...continues

Momentum and projectile motion.

A shell is fired from a gun with a muzzle velocity of 14 m/s, at an angle of 60° with the horizontal. At the top of the trajectory, the shell explodes into two fragments of equal mass (Fig. 9-30). One fragment, whose speed immediately after the explosion is zero, falls vertically. How far from the gun does the other fragment la ...continues

A momentum problem.

A rocket, which is in deep space and initially at rest relative to an inertial reference frame, has a mass of 2.65 105 kg, of which 2.00 105 kg is fuel. The engine is fired for 250 s, during which fuel is consumed at the rate of 480 kg/s. The speed of the exhaust product relative to the rocket is 3.23 km/s. What is the rock ...continues

Center Mass problem.

A 60-kg woman leaps vertically from a crouching position in which her center of mass is 30 cm above the ground. As her feet leave the floor her center of mass is 62 cm above the ground; it rises to 105 cm at the top of her leap. What average force was exerted on her by the ground during the jump? What maximum speed does sh ...continues

a momentum problem

In Fig. 9-32a, a 5.1 kg dog stands on an 21 kg flatboat and is 6.1 m from the shore. He walks 2.1 m on the boat toward shore and then stops. Assuming there is no friction between the boat and the water, find how far the dog is then from the shore? (Hint: See Fig. 9-32b. The dog moves leftward; the boat moves rightward; but does ...continues