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velikii [3]
3 years ago
6

A ball is thrown straight up from the ground with an unknown velocity. It returns to the ground after 4.0seconds. With what velo

city did it leave the ground?
Physics
2 answers:
lbvjy [14]3 years ago
8 0
V = 1/2at^2

a = 9.8 m/2^2 (constant)
t = 4.0 s

1/2 • 9.8 • 4^2
1/2 • 9.8 • 16

= 78.4 m/s
irakobra [83]3 years ago
3 0

Answer:

The ball was thrown at approximately 19.6m/s.

Explanation:

Assuming that there is no air resistance (or drag) in this question, the time to go up is the same to go down. Therefore, we can assume that it takes 2 seconds to go up and then 2 seconds to go down (4 seconds in total).

On Earth's surface, gravity is approximately 9.8m/s^{2}. Notice the s^{2} meaning that gravity is given in terms of acceleration. As it's an acceleration, it means that velocity changes at a rate of 9.8 meters per second. As we have 2 seconds of deceleration going up, we have a starting speed of  2 * 9.8m/s = 19.6m/s .

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3 years ago
Bromine is a liquid at room temperature. The volume of a sample of bromine is measured in a 50 beaker and a 100 ml beaker. How w
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Answer:

The comparisons are;

The height of the bromine in the 50 ml beaker will be twice that of the 100 ml beaker

The measurement of the volume with the 50 ml beaker will be more accurate than the measurement taken with the 100 ml beaker, because the differences in the height of the bromine in the 50 ml beaker is more obvious than the differences measured with the 100 ml beaker.

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2) A liquid will assume the shape of a container in which it is placed

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Running with an initial velocity of +11m/s, a horse has an average acceleration of -1.81m/s 2 . How long does it take for the ho
Ronch [10]

Answer:

2.49 seconds

Explanation:

From the question,

a = (v-u)/t............................ Equation 1

Where a = acceleration, v = final velocity, u = initial velocity, t = time

Make t the subject of the equation

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