Answer:
Force = 485000 Newton.
Explanation:
Given the following data;
Mass = 485000 kg
Initial velocity = 20m/s
Final velocity = 25m/s
Time, t = 5 seconds
To find the force;
First of all, we would calculate the acceleration of the train i.e the rate of change of the velocity of the train with respect to time.
Mathematically, acceleration is given by the equation;
Where;
a is acceleration measured in
v and u is final and initial velocity respectively, measured in
t is time measured in seconds.
Substituting into the equation, we have;
Acceleration = (25 - 20)/5
Acceleration = 5/5
Acceleration = 1m/s²
Force is given by the multiplication of mass and acceleration.
Mathematically, Force is;
Force = mass * acceleration
Force = 485000 * 1
Force = 485000 Newton.
Answer:
E) be two times larger.
Explanation:
As we know that the relation between the resistance and the resistivity of the wire is given as:
where:
resistivity of the wire
length of wire
area of wire
resistance
Now, when the length of the wire is four times the initial length then for the resistance to remain constant:
where:
area of the new wire
we know that area of the cross section of wire is given as:
Hence the radius must be twice of the initial radius for the resistance to be constant when length is taken four times.
The answer to your question is A.
Answer: h = 20.92 m
Explanation: By using the law of conservation of energy, the kinetic energy of the ball equals it potential energy.
Kinetic energy =mv^2/2
Potential energy = mgh
Where m = mass of the object, v = velocity of object = 23.5 m/s
g = acceleration due gravity = 9.8 m/s^2
mv^2/2 = mgh
m cancels out each other on both sides , hence we have that
v^2 = 2gh.
We want the ball to move towards the wall (horizontal motion), hence we need the horizontal component of the velocity since the velocity is inclined at an angle of 30.5 to the ground (horizontal).
Hence v = 23.5 × cos 30.5, v = 20.248 m/s
Recall that v^2 = 2gh
(20.248)^2 = 2×9.8×h
409.98 = 19.6 h
h = 409.98/ 19.6
h = 20.92 m
Answer:Even things that appear to be at rest move.
When we describe the motion of one object with
respect to another, we say that the object is moving
relative to the other object.
• A book that is at rest, relative to the table it lies
on, is moving at about 30 kilometers per second
relative to the sun.
• The book moves even faster relative to the center
of our galaxy.
Explanation: