Answer:
Option(B),option(C) and Option(D) are the correct answer to the given question .
Explanation:
- In the option(B) if we apply the force to stop the car. The motion and force of car is in the opposite direction .Suppose the person is moving the car to the straight and person immediately apply break the back wheel of the car is stop this means that force and direction of motion is opposite that's why this is correct .
- In the option(C) the ball and batsman hinting the ball is in the opposite direction .Suppose the ball is coming to the batsman to the right and it hits to the left its a opposite direction Therefore in this the force and direction of motion is opposite that's why this is correct .
- In the option(D) if the person drawing water from a well there is always upward force is applied but there is always motion is there i.e downward force i,e mg.that's why force and direction of motion is opposite that's why this is correct .
- In the option(A) the force of opening the door of force and the motion is in the same direction therefore it is not the against the direction of motion that's why this option is incorrect .
Answer:
i love life forever and always
Explanation:
The work done in the spring is calculated to be 2.8 J
<h3>What is Hooke's law?</h3>
Hooke's law states that, the extension of a given material is directly proportional to the applied force as long as the elastic limit is not exceeded . First, we must bear in mind that the material must remain within the elastic limit for us to apply the Hooke's law in solving the problem.
Now;
From Hooke's law;
F = Ke
F = force applied
K = force constant
e = extension
F = W = mg = 2.50 - kg * 9.8 m/s^2 = 24.5 N
K = 24.5 N/ 2.76 * 10^-2
K = 888 N/m
e = F/K
F = W = 1.25 - kg * 9.8 m/s^2 = 12.25 N
e = 12.25 N/ 888 N/m = 0.014 m or 1.4 cm
Work done by an external agent = 1/2 Kx^2
= 0.5 * 888 * (8 * 10^-2)^2
= 2.8 J
Learn more about Hoke's law:brainly.com/question/13348278
#SPJ1
Answer:
Explanation:
The minimum height of a space shuttle from the surface of the earth is 304 kilometers.
So according to this data we calculate the value to g at that height.
We have the formula:
where:
g' = the acceleration due to gravity at the given height 'h' above the earth
R = radius of the earth
g = the acceleration due to gravity at the surface of the earth
Now, using eq. (1)
The efficiency of an ideal Carnot heat engine can be written as:
where
is the temperature of the cold region
is the temperature of the hot region
For the engine in our problem, we have
and
, so the efficiency is