Two masses (m1 = 15 kg and m2 = 20 kg) are connected by
a massless cord and placed on a horizontal, frictionless surface. The
two-mass system is pulled to the right by a force FA = 60 N using a
cord that makes an angle of 40 degrees with the horizontal. The masses
remain on the horizontal surface. There is no vertical motion.
(a) Draw the free body diagrams for the two masses, properly labeling all forces.
(b) What is the normal force between mass m2 and the horizontal surface?
(c) What is the acceleration of the system?
(d) What is the tension FT in the cord between the two masses?
A free particle with mass m is subjected to a
time-dependent force F(t) = F0 exp(-t/τ) for t > 0. F0 and
τ are constants.
(a) Find the velocity v(t) of the particle as a function of time, given that v = 0 at time t = 0.
(b) What is the total work done on the particle by the force as t --> infinity?
A 36 g bullet with a speed of 350 m/s strikes a 8 cm thick
fence post. The bullet is retarded by an average force of 3.6*103 N
while traveling all the way through the board.
(a) What speed does the bullet have when it emerges?
(b) How many such boards could the bullet penetrate?