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3 years ago

A student throws a ball straight down off a very high building with a magnitude of 3m/s and

Physics

1 answer:

ollegr [7]3 years ago

8 0

Answer:

Vf = 22.62 [m/s] in 2 seconds.

Explanation:

In order to solve this problem we must use the following kinematics equation

$v_{f} = v_{i} + (g*t)$

where:

Vf = final velocity [m/s]

Vi = initial velocity = 3 [m/s]

g = gravity acceleration = 9.81 [m/s^2]

t = time = 2 [s]

Vf = 3 + (9.81*2)

Vf = 22.62 [m/s]

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A "590-W" electric heater is designed to operate from 120-V lines.

lukranit [14]

Answer:

a) 24.4 Ω

b) 4.92 A

c) 495.9 W

c. It will be larger. The resistance will be smaller so the current drawn will increase, increasing the power.

Explanation:

The formula for power is:

P = IV

where,

P = Power of heater = 590 W

V = Voltage it takes = 120 V

I = Current Drawn = ?

Therefore,

590 W = (I)(120 V)

I = 590 W/120 V

I = 4.92 A

From Ohm's Law:

V = IR

R = V/I

Therefore,

R = 120 V/4.92 A

R = 24.4 Ω

For constant resistance and 110 V the power becomes:

P = V²/R

Therefore,

P = (110 V)²/24.4 Ω

P = 495.9 W

If the resistance decreases, it will increase the current according to Ohm's Law. As a result of increase in current the power shall increase according to formula (P = VI). Therefore, correct option is:

c. It will be larger. The resistance will be smaller so the current drawn will increase, increasing the power.

7 0

3 years ago

What is serve in volleyball?

madreJ [45]

Underhand serve is a type of volleyball serve in which a player holds the ball with one hand and swings the other hand in an arc motion, striking under the ball with a fist to put it into play. An underhand serve is the most common serve for beginners.

3 0

3 years ago

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Why is the contribution of the wavelets lying on the back of secondary wave front zero?

Tresset [83]

Answer:

The contribution of the wavelets lying on the back of the wave front is zero because of something known as the Obliquity Factor. It is assumed that the amplitude of the secondary wavelets is not independent of the direction of propagation, Sources: byju's.com

3 0

2 years ago

Read 2 more answers

9. Since current is the rate at which charge is flowing, if the current in the circuit decreases, what does that mean about the

TiliK225 [7]

Answer:

Electric current is defined as the rate of flow of electric charge in a circuit from point one point to another. This is carried by electrically charged particles within the circuit. Current is represented by the symbol I and its unit measured in Amperes. It is therefore related to the voltage and resistance of the circuit. If the current in the circuit reduces, the rate at which the charge and current on the capacitor reduces also proportionally in an exponential manner.

Explanation:

Since a decrease in the flow of current in the circuit is observed, the implication for the rate at which the charge and voltage on the capacitor is also an exponential decrease in the rate of flow with time. This is because the electric current is directly proportional to the electric charge and the time.

5 0

3 years ago

swings a 5.5 kg cup of water in a vertical circle of radius 1.9 m. (a) What minimum speed must the cup have in this demo if the

Tanzania [10]

Answer:

4.32

Explanation:

The centripetal acceleration of any object is given as

A(cr) = v²/r, where

A(c) = the centripetal acceleration

v = the linear acceleration

r = the given radius, 1.9 m

Since we are not given directly the centripetal acceleration, we'd be using the value of acceleration due to gravity, 9.8. This means that

9.8 = v²/1.9

v² = 1.9 * 9.8

v² = 18.62

v = √18.62

v = 4.32 m/s

This means that, the minimum speed the cup must have so as not to get wet or any spill is 4.32 m/s

6 0

3 years ago