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Alexus [3.1K]
3 years ago
5

An entertainer juggles balls while doing other activities. In one act, she throws a ball vertically upward, and while it is in t

he air, she runs to and from a table 5.50 m away at an average speed of 3.00 m/s, returning just in time to catch the falling ball. (a) With what minimum initial speed must she throw the ball upward to accomplish this feat? (b) How high above its initial position is the ball just as she reaches the table?
Physics
1 answer:
sp2606 [1]3 years ago
3 0

Answer:

a) 17.97 m/s

b) 16.5 m

Explanation:

The total distance that she runs is twice the distance between her and the table, which is 5.5 * 2 = 11m

So the time she would need to run that distance at a rate of 3m/s is

t = 11/3 = 3.67s

This is also the time it takes for the ball to be thrown up and down, which is twice the time it needs to reach the top, its maximum height at v = 0 m/s

So the time for the ball to reach maximum height is 3.67 / 2 = 1.83 s

Let g = 9.8m/s2. For the ball to get to 0 within 1.83s at the deceleration of 9.8m/s. Its initial speed must be

v = gt = 9.8*1.83 = 17.97 m/s

As she reaches the table within half of the total time (3.67 /2 = 1.83s), the position of the ball would be

h = vt + gt^2/2 = 17.97*1.83 - 9.8*1.83^2/2 = 16.5 m

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Answer:

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Explanation:

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Let downward velocity is positive then upward velocity is negative

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Time is given as 1800 sec

We know that acceleration is rate of change of velocity

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According to newton second law

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4 years ago
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The density of sample is 5 g/cm3

Given:

volume of sample = 20 cm3

mass of sample = 100 grams

To Find:

density of sample

Solution: Density is the measure of how much “stuff” is in a given amount of space. For example, a block of the heavier element lead (Pb) will be denser than the softer, lighter element gold (Au). A block of Styrofoam is less dense than a brick. It is defined as mass per unit volume

density = mass/volume

d = 100/20

d = 5 g/cm3

So, density of sample is 5 g/cm3

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2 years ago
Photograph E shows a rechargeable torch. When a student shakes the torch, the magnet moves through the coil and back again. This
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Answer:

a) according to Faraday's law , b) creating a faster movement, placing more turns on coil

Explanation:

a) The voltage is induced in the coil by the relative movement between it and the magnet, therefore according to Faraday's law

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In this case, the magnet is involved, so the value of the magnetic field varies with time, since the number of lines that pass through the loop changes with movement.

This voltage creates a current that charges the battery

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3 years ago
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3 years ago
A person is attracted towards the center of the earth by an 800 N gravitational force. The force with which the earth is attract
suter [353]

Answer:

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