Kinetic energy is directly proportional to the mass of the object and to the square of its velocity: K.E. = 1/2 m v2.
Explanation:
Let h is the height of the plane above ground. x is the horizontal distance between the ground and the airport. Let s(t) is the distance between the plane and the airport. So,
...........(1)
Given, h = 4, x = 40 and s(t) = -20 mph
Differentiate equation (1) wrt t
When x = 40,
So, the speed of the airplane is 241.14 m/s. Hence, this is the required solution.
Answer:
B. +m
Explanation:
The magnification of an image is defined as the ratio between the size of the image and of the object:
where we have
y' = size of the image
y = size of the object
There are two possible situations:
- When m is positive, y' has same sign as y: this means that the image image is upright
- When m is negative, y' has opposite sign to y: this means that the image is upside down
Therefore, the correct option representing an upright image is
B. +m
When a footballer collides with the goal post, the forces at work are the action and reaction forces. The player will exert an action force on the goal post, and then a reaction force from the goal post will stop the player. The reaction force call will cause pain and even injury to the player.
Thermal energy quantifies the amount of heat present in the body and is calculated through the equation,
H = mcpdT
where H is the heat, m is the mass, cp is the specific heat, and dT is the temperature difference. If all things are constant, and the thermal energy is halved then, dT should also be reduced to half.