TRUE OR FALSE Determine if the following statements are true or false.

Robert, a stuntman, projects himself from a height of 50.0 meters in a horizontal direction. He safely lands at a horizontal dis

Olin [163]

To get this we need to know how long he was traveling. To know that we need to solve for the time it took for him to hit the ground. This is given by the vertical height he started at and the equation of motion for falling objects. The position function is
Y= -(9.8/2)t^2 + 50 = 0
t=3.19s
That's how long he's in the air. When he hits the ground he stops moving forward so this is also the amount of time he was moving at 100m/s horizontally. Now use speed distance relationship
X=vt
And solve for v
100m/3.19s = 31.35m/s

3 0

4 years ago

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A stone is thrown vertically upward with a speed of 15.5 m/s from the edge of a cliff 75.0 m high .

rjkz [21]

a) 2.64 s

We can solve this part of the problem by using the following SUVAT equation:

$s=ut+\frac{1}{2}at^2$

where

s is the displacement of the stone

u is the initial velocity

t is the time

a is the acceleration

We must be careful to the signs of s, u and a. Taking upward as positive direction, we have:

- s (displacement) negative, since it is downward: so s = -75.0 m

- u (initial velocity) positive, since it is upward: +15.5 m/s

- a (acceleration) negative, since it is downward: so a= g = -9.8 m/s^2 (acceleration of gravity)

Substituting into the equation,

$-75.0 = 15.5 t -4.9t^2\\4.9t^2-15.5t-75.0 = 0$

Solving the equation, we have two solutions: t = -5.80 s and t = 2.84 s. Since the negative solution has no physical meaning, the stone reaches the bottom of the cliff 2.64 s later.

b) 10.4 m/s

The speed of the stone when it reaches the bottom of the cliff can be calculated by using the equation:

$v=u+at$

where again, we must be careful to the signs of the various quantities:

- u (initial velocity) positive, since it is upward: +15.5 m/s

- a (acceleration) negative, since it is downward: so a = g = -9.8 m/s^2

Substituting t = 2.64 s, we find the final velocity of the stone:

$v = 15.5 +(-9.8)(2.64)=-10.4 m/s$

where the negative sign means that the velocity is downward: so the speed is 10.4 m/s.

c) 4.11 s

In this case, we can use again the equation:

$s=ut+\frac{1}{2}at^2$

where

s is the displacement of the package

u is the initial velocity

t is the time

a is the acceleration

We have:

s = -105 m (vertical displacement of the package, downward so negative)

u = +5.40 m/s (initial velocity of the package, which is the same as the helicopter, upward so positive)

a = g = -9.8 m/s^2

Substituting into the equation,

$-105 = 5.40 t -4.9t^2\\4.9t^2 -5.40 t-105=0$

Which gives two solutions: t = -5.21 s and t = 4.11 s. Again, we discard the first solution since it is negative, so the package reaches the ground after

t = 4.11 seconds.

5 0

3 years ago

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How long must it take for a communications satellite to make one complete orbit around the earth? (such an orbit is said to be g

vitfil [10]

The time period of the communications satellites must be 24 hours to make one complete orbit around the earth.

An object that has been placed into orbit in space on purpose is known as a satellite or artificial satellite. Most spacecraft, with the exception of passive satellites, contain a means of generating electricity for the electronics they carry, such as solar cells or radioisotope thermoelectric generators.

A communications satellite is a man-made spacecraft that uses a transponder to relay and amplify radio telecommunication signals. It establishes a channel of communication between a source transmitter and a receiver situated at various points on Earth.

Most satellites that orbit the Earth do so between 160 and 2,000 kilometers above the surface. Because of how closely the satellites are orbiting the Earth, this orbital regime is known as low Earth orbit or LEO. The normal orbital period for satellites in low Earth orbit (LEO) is between 90 and 2 hours.

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5 0

2 years ago

If a transformer has 50 turns in the primary winding and 10 turns on the secondary winding, what is the reflected resistance in

Elza [17]

Answer:

The reflected resistance in the primary winding is 6250 Ω

Explanation:

Given;

number of turns in the primary winding, $N_P$ = 50 turns

number of turns in the secondary winding, $N_S$ = 10 turns

the secondary load resistance, $R_S$ = 250 Ω

Determine the turns ratio;

$K = \frac{N_P}{N_S} \\\\K = \frac{50}{10} \\\\K = 5$

Now, determine the reflected resistance in the primary winding;

$\frac{R_P}{R_S} = K^2\\\\R_P = R_SK^2\\\\R_P = 250(5)^2\\\\R_P = 6250 \ Ohms$

Therefore, the reflected resistance in the primary winding is 6250 Ω

6 0

4 years ago

The formula for electrical power is p = i v. Which is the equivalent equation solved for i? startfraction p over v endfraction =

Anettt [7]

The equivalent formula for p = iv is the startfraction p over v endfraction = i

In physics, power measures the rate of transfer of electrical energy through a circuit per unit of time. It is denoted by P and is measured using the SI unit of power (watts or 1 joule/second). Electrical energy is usually supplied by batteries and produced by generators.

There are three types of power, true, reactive, and apparent, which are related in trigonometric form. This is called the power triangle. A power triangle that relates apparent power to active and reactive power. Power is measured in watts. One watt equals one joule per second.

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8 0

1 year ago