y = y0 +v0*t +0.5at^2
where y0 = initial vertical position = 22m
y = final vertical position = 0m
v0 = initial vertical velocity = 0 m/s
a = acceleration = -9.8 m/s^2
t = time in seconds
0 = 22 +0*t + 0.5(-9.8)t^2
t^2 = 22/4.9 = 4.49 s^2
t = 2.12 s
So it traveled 35m in 2.12 s
the horizontal distance traveled is determined by:
x = x0 +v0*t +0.5at^2
but here a in the horizontal direction is 0 m/s^2
and v0 is in the velocity in the horizontal direction in this equation
35 m = 0 +v0*t
35 m = v0(2.12 s)
v0 = 16.5 m/s
So the ball was kicked 16.5 m/s in the horizontal direction
The Earth's gravitational pull and the table's force are of equal magnitude and in opposite directions, they balance each other.
<u>Explanation:</u>
A book placed on a surface have two forces acting on it which are, a force that pulls it toward the ground in a downward direction, that is gravitational pull and a second which is acted on the book on upward direction making a balance on the object.
This follows Newton’s third law of motion that states every action has an equal and opposite reaction.
The roughness of the surface should be varied by the students tp test the hypothesis in the best possible way.
Explanation:
As the hypothesis stated the relation between roughness of the surface and the distance covered by the marble, students first need to find the independent variable among these two. The independent variable will be the one which will not depend on the result of the other variable. But there will be change in the dependent variable on changing the independent variable.
So here the independent variable is the roughness of the surface as per the hypothesis. And the dependent variable will be distance covered by the marble.
So the students should vary the independent variable and check for desired changes in the dependent variable for confirmation of hypothesis.
Thus, the roughness of the surface should be varied by the students tp test the hypothesis in the best possible way.
Answer:
Total work done is 2606.08 J.
Explanation:
Given :
Mass of box , m = 23 kg .
Force applied , F = 100 N .
Angle from horizon , .
Coefficient of kinetic friction , .
Distance travelled by box , d = 34 m .
Now ,
Total work done = work done by boy + work done by friction.
Hence , this is the required solution.
Sawing the piece of wood in half is a physical change,
because no new substances are formed that weren't there
before the sawing.
Burning wood produces carbon monoxide and carbon dioxide
that weren't there before the burning. That's a chemical change.
Rust forming on iron is iron oxide that wasn't there before the
rusting. That's a chemical change.
The green that appears on copper is copper oxide that wasn't
there before the green appeared. That's a chemical change.