Whenever the motion of an object <em><u>changes</u></em> . . . speeding up, or slowing down,
or changing direction . . . that change is called "<em><u>acceleration</u></em>". Acceleration is
produced by force on the object.
If there is <em><u>no force</u></em> on the object, then there is no acceleration. That means that
its motion <em><u>doesn't change</u></em>. The object remains in constant, uniform motion ...
moving with steady speed, in a straight line.
No force is necessary to <em><u>keep</u></em> an object moving, only to <em><u>change</u></em> its motion.
Answer:
Permanent magnets can lose their magnetism if they are dropped or banged on enough to bump their domains out of alignment
Explanation:
Answer:
The maximum height reached by the body is 313.6 m
The time to return to its point of projection is 8 s.
Explanation:
Given;
initial velocity of the body, u = 78.4 m/s
at maximum height (h) the final velocity of the body (v) = 0
The following equation is applied to determine the maximum height reached by the body;
v² = u² - 2gh
0 = u² - 2gh
2gh = u²
h = u²/2g
h = (78.4²) / (2 x 9.8)
h = 313.6 m
The time to return to its point of projection is calculated as follows;
at maximum height, the final velocity becomes the initial velocity = 0
h = v + ¹/₂gt²
h = 0 + ¹/₂gt²
h = ¹/₂gt²
2h = gt²
t² = 2h/g

Answer:
1. C
2. B
5. C
B. The recoil is a result of conservation of momentum. The force of the ignition of the gunpowder that pushes the bullet forward will be balanced out by also pushing against the gun.
Newton's third law is displayed in each of these questions.