An object in free fall motion is under the influence of gravitational force only
The height and time are;
(a) The height of the cliff, h ≈ <u>8.00 meters</u>
(b) The time it takes the rock to rich the ground with the same speed going downward is approximately <u>0.67</u><u> seconds</u>
The reason the above values are correct are as follows:
The given parameters are;
The time it takes for the rock to hit the ground when thrown straight up from the cliff, t = 2.45 s
The initial velocity with which the rock is thrown, u = 8.75 m/s
(a) To find the height of the cliff
Solution
The kinematic equation of motion is s = y₀ + u·t + (1/2)·g·t²
The time it takes to maximum height, = 8.75/9.81
The time it takes to get back to the cliff edge when thrown = 2 × 8.75/9.81
The time taken to fall at the velocity of <em>u</em> downwards from the cliff edge, , is given as follows;
= 2.45 - 2 × 8.75/9.81 ≈ 0.666
Height of cliff, h = 8.75×(2.45 - 2 × 8.75/9.81) + (1/2) × 9.81 × (2.45 - 2 × 8.75/9.81)² ≈ 8
The height of the cliff, h ≈ <u>8.00 meters</u>
(b) The time it takes the rock to rich the ground when thrown straight down art the same speed, (calculates above) = ≈ <u>0.67 seconds</u>
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Learn more about free fall motion here:
<u>Correct Question:</u>
Calculate the distance (in km) charlie runs if he maintains an average speed of 8 km/hr for 1 hour
<u>Answer:</u>
The total distance covered by Charlie is 8 km in 1 hour.
<u>Explanation:</u>
The average velocity as given in the question is,
v = 8 km/hr
Total time taken,
As we know the formula to evaluate the total distance d when the average velocity and time is given;
Hence, the total distance covered by Charlie in 1 hour will be 8 km.
Answer : The wavelength of photon is,
Explanation : Given,
Energy of photon =
Formula used :
As,
So,
where,
= frequency of photon
h = Planck's constant =
= wavelength of photon = ?
c = speed of light =
Now put all the given values in the above formula, we get:
Conversion used :
Therefore, the wavelength of photon is,
Answer:
Approximately .
Assumption: the ball dropped with no initial velocity, and that the air resistance on this ball is negligible.
Explanation:
Assume the air resistance on the ball is negligible. Because of gravity, the ball should accelerate downwards at a constant near the surface of the earth.
For an object that is accelerating constantly,
,
where
In this case, is the same as the change in the ball's height:
. By assumption, this ball was dropped with no initial velocity. As a result,
. Since the ball is accelerating due to gravity,
.
.
In this case, would be the velocity of the ball just before it hits the ground. Solve for
.
.