1) 29.4 N
The force of gravity between two objects is given by:
where
G is the gravitational constant
M and m are the masses of the two objects
r is the separation between the centres of mass of the two objects
In this problem, we have
(mass of the Earth)
(mass of the box)
(Earth's radius, which is also the distance between the centres of mass of the two objects, since the box is located at Earth's surface)
Substituting into the equation, we find F:
2) 
Let's now calculate the ratio F/m. We have:
F = 29.4 N
m = 3.0 kg
Subsituting, we find
This is called acceleration of gravity, and it is the acceleration at which every object falls near the Earth's surface. It is indicated with the symbol 
.
We can prove that this is the acceleration of the object: in fact, according to Newton's second law,
where a is the acceleration of the object. Re-arranging,
which is exactly equal to the quantity we have calculated above.
Phenyl oxalate ester is responsible for the luminescence in aglow stick<span>. The reaction with hydrogen peroxide </span>causes<span> the liquid inside a </span><span>glow stick to glow</span>
Answer;
D. rocket engines are not dependent on oxygen from the air.
Explanation;
-Jet engines and rockets work on the same principle. They produce thrust through an internal pressure difference and, as explained by Newton’s Third Law of Motion, eject exhaust gases in an equal and opposite direction.
-The main difference between them is that jets get the oxygen to burn fuel from the air and rockets carry their own oxygen, which allows them to operate in space.
Additionally, Jet engines have two openings (an intake and an exhaust nozzle). Rocket engines only have one opening (an exhaust nozzle).
Answer:
The work done by the bird is 0.762 J
Explanation:
Given;
force applied by the bird, f = 10 N
distance the bird moved the worm, d = 3 inches = 0.0762 m
The work done by the bird is given by;
W = F x d
where;
W is the work done by the bird
d is the distance the bird moved the load
Substitute the given values and estimate the work done by the bird;
W = 10 x 0.0762
W = 0.762 J
Therefore, the work done by the bird is 0.762 J
Answer:
The acceleration of the ball is 
Explanation:
From the question we are told that
The maximum height the ball reachs is 
The horizontal component of the initial velocity of the ball is 
The vertical component of the initial velocity of the ball is 
The vertically motion of the ball can be mathematically represented as
Here the final velocity at the maximum height is zero so 
Making the acceleration 
the subject we have
substituting values
The negative sign shows that the direction of the acceleration is in the negative y-axis
