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 that the acceleration is constant?

2.A vessel at rest explodes, breaking into three pieces. Two pieces, having equal mass, fly off perpendicular to one another with the same speed of 30 m/s. The third piece has three times the mass of each other piece. What are the magnitude and direction of its velocity immediately after the explosion?

3. An object is tracked by a radar station and found to have a position vector given by
r(vector) = (3500 - 160t)i + 2700j + 300k,
with r(vector) in meters and t in seconds. The radar station's x-axis points east, its y-axis north, and its z-axis vertically up. If the object is a 250kg meteorological missile, what are:
a) Its linear momentum
b) Its direction of motion
c) The net force on it

Solution Preview

1. (a) It is nonsense to ask "average" something at instantaneous time because "average" must involve a time interval.

(b) For the average power during a 30 s interval, P=F*v. Assume the acceleration is constant, F is constant and v is the average velocity ...

Solution Summary

This response shows how to calculate power using formula, as well as mentioning conservation of momentum and direction of momentum to solve the equations.

... resistance of the water to motion at the low velocities involved. ... lands on barge 2 = 20000 kg.m/s → Final velocity of car on barge 2 = 0. Momentum of the ...

... is, power = work/ time = 125J/10s = 12.5J/s (or Watts). Kinetic energy = 1/2 xmxv^2 = 1/2 x 600Kg x 25m/sx 25m/s = 187,500J. Momentum = mass x velocity = 600kg ...

... The momentum after the two are coupled is equal to their combined weight times their velocity. ... mass of the railroad cars to find their velocities after a ...

... If initial velocity of the neutron is v0 and velocities of neutron and ... Hence according to law of conservation of linear momentum mv0 = mv1 + Mv2 and as the ...

... first car race in which all the vehicles were solar powered. ... of 73.0 kg runs with a constant forward velocity of 1.50 m/s. What is the athlete's momentum? ...

... kg ball is thrown upward at a initial velocity of 9.1 m ... How much power did the person expend running up he ... This solution consist of Momentum work and power etc. ...

... vertically) in 20 s. (a) How much power does she ... same speed and angle, what is the change in its momentum? ... kg ball is thrown horizontally with a velocity of 15 ...

... important in allowing the wind to gain momentum and to ... Air movement must attain a certain velocity or become an ... Winds with velocities of less then 12-19 km/hr ...

... 11. The magnitude of the angular momentum is: L = MvR. ... Where the initial velocities in each direction are (as a function of the initial velocity v0 and the ...