Calculate the average speed (in km/hr) of Charlie whonruns to the store 4 km away in 30 minutes

Alternating current changes the ____ of the current flow

Anuta_ua [19.1K]

Answer:

Direction

Explanation:

There are two types of electric current:

- DC (Direct current): in a direct current, the direction of the flow of the current is constant; this means that it does not change. This means that the potential difference supplied has always the same direction, so that the electrons travel always in the same direction through the circuit

- AC (Alternating current): in an alternating current, the direction of the flow of the current is constantly reverses. This means that the direction of the potential difference supplied constantly changes, therefore the electrons travel half the time in one direction and half the time in the opposite direction.

5 0

3 years ago

You are in charge of designing a movie stunt for a new Fast and Furious film. In this scene a stunt person has to jump from a br

blondinia [14]

Answer:

103.5 meters

Explanation:

Given that a stunt person has to jump from a bridge and land on a boat in the water 22.5 m below. The boat is cruising at a constant velocity of 48.3 m/s towards the bridge. The stunt person will jump up at 6.45 m/s as they leave the bridge.

The time the person will jump to a certain spot under the bridge can be calculated by using the formula below:

h = Ut + 1/2gt^2

since the person will fall under gravity, g = 9.8 m/s^2

Also, let assume that the person jump from rest, then, U = 0

Substitute h, U and g into the formula above

22.5 = 1/2 * 9.8 * t^2

22.5 = 4.9t^2

t^2 = 22.5/4.9

t^2 = 4.59

t = $\sqrt{4.592}$

t = 2.143 seconds

From definition of speed,

speed = distance /time

Given that the boat is cruising at a constant velocity of 48.3 m/s towards the bridge, substitute the speed and the time to get the distance.

48.3 = distance / 2.143

distance = 48.3 * 2.143

distance = 103.5 m

Therefore, the boat should be 103.5m away from the bridge at the moment the stunt person jumps?

3 0

3 years ago

A tennis ball is thrown vertically upward with an initial velocity of +6.2 m/s. What will the ball’s velocity be when it returns

anastassius [24]

Answer:

$v_{f}=-6.2 m/s$

Explanation:

The ball will rise decreasing its speed until it reaches the highest point where its speed will be zero. From this point the tennis ball will begin to fall again, in the free fall the tennis ball will gain speed but now in the opposite direction. When it returns to the same point where it was launched, its speed will be the same as the one that was launched but with the opposite sign.

$v_{f}=-6.2 m/s$

We can check this using the equation:

$v_{f}^2=v_{i}^2+2gh$

where $v_{i}=+6.2 m/s$

ang h is the height, but because the ball returns to the same point where it started, h =0

then

$v_{f}^2=v_{i}^2$

$v_{f}=v_{i}$

the initial and final velocity will be the same in number, but we know that the ball is going in the opposite direction, so the final velocity must have the opposite sign from the initial velocity

so if $v_{i}=+6.2 m/s$ ,

$v_{f}=-6.2 m/s$

4 0

2 years ago

The index of refraction of Sophia's cornea is 1.387 and that of the aqueous fluid behind the cornea is 1.36. Light is incident f

shtirl [24]

Answer:

17.85°

Explanation:

To find the angle to the normal in which the light travels in the aqueous fluid you use the Snell's law:

$n_1sin\theta_1=n_2sin\theta_2$