Chapter 4 Problems
44. The pilot of an airplane notes that the compass indicates a heading due west. The airplane’s speed
relative to the air is 150 km/h. The air is moving in a wind at 30.0 km/h toward the north. Find the
velocity of the airplane relative to the ground.
Chapter 5 Problems
22. Three forces acting on an object are given by F1 = (-2.00i + 2.00j) N, and F2 = (5.00i
– 3.00j) N, and F3 = (-45.0i) N. The object experiences an acceleration of magnitude 3.75
m/s2. (a) What is the direction of the acceleration? (b) What is the mass of the object? (c)
If the object is initially at rest, what is its speed after 10.0 s? (d) What are the velocity
components of the object after 10.0 s?
30. A block slides down a frictionless plane having an inclination of θ = 15.0°. The block
starts from rest at the top, and the length of the incline is 2.00 m. (a) Draw a free-body
diagram of the block. Find (b) the acceleration of the block and (c) its speed when it
reaches the bottom of the incline.
45. In the system shown in the figure below, a horizontal force Fx acts on an object of
mass m2 = 8.00 kg. The horizontal surface is frictionless. Consider the acceleration of the
sliding object as a function of Fx. (a) For what values of Fx does the object of mass m1 =
2.00 kg accelerate upward? (b) For what values of Fx is the tension in the cord zero? (c)
Plot the acceleration of the m2 object versus Fx. Include values of Fx from -100 N to +100
N.
47. A block is given an initial velocity of 5.00 m/s up a frictionless incline of angle θ =
20.0°, as in the figure below. How far up the incline does the block slide before coming
to rest?