Answer:
(a) 9 m/s
(b) 108 J
(c) 90 kg m/s
(d) 45 m/s
Step-by-step explanation:
Part (a)
By the second law of Newton, the acceleration is equal to
Where F is the net force and m is the mass. So, replacing F = 18 N and m = 2 kg, we get
Then, the acceleration of the object while the force is applied is 9 m/s²
Part (b)
The increase of the kinetic energy can be calculated as
Where m is the mass, vf is the final velocity and vi is the initial velocity. By the kinematic equations, we have the following equality
Where a is the acceleration and x is the distance traveled. Replacing this equation on the equation above, we get
Then, we need to replace m = 2kg, a = 9 m/s² and x = 6 m
Therefore, the kinetic energy increase 108 J.
Part (c)
The change in the momentum can be calculated as
Where F is the force and t is the time. Replacing F = 18N and t = 5 s, we get
So, the object's momentum increases 90 kg m/s
Part (d)
The change in momentum is also equal to
Where (vf - vi) is the object's speed increase. So, solving for (vf - vi), we get
Finally, replace Δp = 90 kg m/s and m = 2 kg, we get
Then, the object's speed increase 45 m/s
So, the answers are:
(a) 9 m/s
(b) 108 J
(c) 90 kg m/s
(d) 45 m/s