a ball has a mass of 0.5kg dropped from a cliff top, the ball srtikes the sea below at a velocity of 10m/s.
(a)what is the kinetic energy of the ball as it strikes the sea?
(b) what was its potential energy before it was dropped?
(c)from what height was it dropped?
To answer these questions, we need to understand the concepts of kinetic energy, potential energy, and apply the laws of physics. Let's break down each question and explain how to get the answer.
(a) What is the kinetic energy of the ball as it strikes the sea?
The formula for kinetic energy is given by:
Kinetic energy = 0.5 * mass * velocity^2
In this case, the mass of the ball is 0.5 kg, and the velocity at which it strikes the sea is 10 m/s. Plugging these values into the formula:
Kinetic energy = 0.5 * 0.5 kg * (10 m/s)^2
= 0.5 * 0.5 kg * 100 m^2/s^2
= 25 Joules
Therefore, the kinetic energy of the ball as it strikes the sea is 25 Joules.
(b) What was its potential energy before it was dropped?
Potential energy is associated with an object's position and is determined by its height and mass. The formula for potential energy at a height h is given by:
Potential energy = mass * 9.8 m/s^2 * height
In this case, the mass of the ball is 0.5 kg. To find the potential energy, we need to determine the height from which it was dropped. Let's move on to the next question to find the height.
(c) From what height was it dropped?
To determine the height from which the ball was dropped, we can use kinematic equations. First, we should calculate the time it takes for the ball to fall using the equation of motion:
Distance = (0.5 * acceleration * time^2)
The distance fallen is equal to the height from which it was dropped, and the acceleration due to gravity is 9.8 m/s^2. Rearranging the equation, we get:
time^2 = (2 * distance) / acceleration
Plugging in the known values:
time^2 = (2 * height) / 9.8
time = sqrt((2 * height) / 9.8)
Next, we can use the equation of motion to find the time:
velocity = acceleration * time
10 m/s = 9.8 m/s^2 * time
time = 10 m/s / 9.8 m/s^2
Now, we can substitute this value of time back into the equation for the time it takes to fall:
(10 m/s / 9.8 m/s^2)^2 = (2 * height) / 9.8
height = (10 m/s / 9.8 m/s^2)^2 * 9.8 / 2
Evaluating this expression:
height = 5.10204 meters
Therefore, the ball was dropped from a height of approximately 5.10204 meters.
In summary:
(a) The kinetic energy of the ball as it strikes the sea is 25 Joules.
(b) The potential energy before it was dropped depends on the height. To calculate it, proceed to question (c).
(c) The ball was dropped from a height of approximately 5.10204 meters.
WHAT does "a" stand for?
pefvghfh
(a) K = 1/2 mv^2 - you have the numbers. plug 'em in
(b) PE = KE
(c) s = v^2/2a