Question

1. consider newtons first law of motion to determine which of the following statements are true? list all that apply.

a newtons first law of motion is applicable to both moving and nonmoving objects.
b. if a football is moving upwards and rightwards towards the peak of its trajectory, then there are both rightwards and upwards forces acting upon it.
c. it would take an unbalanced force to keep an object in motion.
d. if an object is at rest, then there are no forces acting upon the object.
e. it would take an unbalanced force to keep an object in motion at a constant velocity.
f. it is the natural tendency of all objects to eventually come to a rest position.
g a pendulum bob is set into its usual back - and - forth periodic motion. after some time (perhaps 10 minutes), the pendulum bob comes to a rest position. this is best explained by the idea of inertia - all objects eventually resist motion.
h. if a 3 - kg rock is thrown at a speed of 2 m/s in a gravity - free environment (presuming one could be found), then an unbalanced force of 6 n would be required to keep the rock moving at a constant speed.
i. it would take an unbalanced force to cause an object to accelerate from rest.

Explanation:

• Statement A: Newton's first law (law of inertia) states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. So, it is applicable to both moving (if no un - balanced force acts, motion continues) and non - moving (remains at rest if no un - balanced force acts) objects.
• Statement B: When a football is moving upwards and rightwards towards the peak of its trajectory, the only force acting on it (neglecting air resistance) is the force of gravity (acting downwards). There is no rightwards or upwards force (except the initial force that set it in motion, but once in motion, the only force is gravity).
• Statement C: According to Newton's first law, an object in motion will stay in motion with constant velocity (no acceleration) if there is no un - balanced force. So, it does not take an un - balanced force to keep an object in motion.
• Statement D: If an object is at rest, it just means the net force acting on it is zero. There can be forces acting on it (e.g., a book on a table has the force of gravity downwards and the normal force upwards, which balance each other).
• Statement E: An object in motion at a constant velocity has zero acceleration. By Newton's first law (\(F = ma\), where \(a = 0\)), the net force \(F=0\). So, it does not take an un - balanced force.
• Statement F: It is not the natural tendency of all objects to come to rest. Objects come to rest because of un - balanced forces like friction. In the absence of un - balanced forces, objects would remain in their state of motion (either at rest or in uniform motion).
• Statement G: A pendulum bob comes to rest because of un - balanced forces like air resistance and friction at the pivot. Inertia is the tendency of an object to resist changes in its state of motion, not to resist motion itself.
• Statement H: In a gravity - free environment, if there is no air resistance (assuming ideal conditions), once the rock is thrown (given an initial velocity), no un - balanced force is required to keep it moving at a constant speed. By Newton's first law, it will continue in its state of motion (constant velocity) unless an un - balanced force acts on it.
• Statement I: By Newton's first law (\(F = ma\)), to cause an object to accelerate (\(a

eq0\)) from rest (\(v = 0\) initially), an un - balanced force (\(F
eq0\)) is required since \(F = ma\) and \(a=\frac{\Delta v}{\Delta t}
eq0\) for acceleration from rest.

Answer:

A. Newton's first law of motion is applicable to both moving and nonmoving objects.
I. It would take an unbalanced force to cause an object to accelerate from rest.