At a drag race, a jet car travels 1/4 mile in 5.2 seconds. What is the final speed of the

A helicopter travels west at 80 mph. It is moving above a car traveling on a highway at 80 mph. Given this information, you can

gavmur [86]

Answer:

d. at the same velocity

Explanation:

I will assume the car is also travelling westward because it was stated that the helicopter was moving above the car. In that case, it depends where the observer is. If the observer is in the car, the helicopter would look like it is standing still ( because both objects have the same velocity). If the observer is on the side of the road, both objects would be travelling at the same velocity. Also recall that, velocity is a vector quantity; it is direction-aware. Velocity is the rate at which the position changes but speed is the rate at which object covers distance and it is not direction wise. Hence velocity is the best option.

5 0

1 year ago

A 5-ft-tall person walks away from the wall at a rate of 2 ft/sec. A spotlight is located on the ground 40 ft from the wall. How

AveGali [126]

Answer:

The rate of change of the height is - 4 ft/s

Solution:

As per the question:

Height of the person, y = 5 ft

The rate at which the person walks away, $\frac{dx}{dt} = 4\ ft/s$

Distance of the spotlight from the wall, x = 40 ft

Now,

To calculate the rate of change in the height, $\frac{dy}{dt}$ of the person when, x = 10 m:

From fig 1.

$\Delta ABC[\tex] ≈ [tex]\Delta PQC[\tex]Thus[tex]\frac{BC}{AB} = \frac{PQ}{QC}$

$\frac{y}{40} = \frac{5}{x}$

xy = 200 (1)

Differentiating the above eqn w.r.t time t:

$x\frac{dy}{dt} + y\frac{dx}{dt} = 0$

Thus

$\frac{dy}{dt} = - \frac{y}{x}\frac{dx}{dt}$ (2)

From eqn (1):

When x = 10 ft

10y = 200

y = 20 ft

Using eqn (2):

$\frac{dy}{dt} = - \frac{20}{10}\times 2 = - 4\ ft$

8 0

2 years ago

No official standard exists for extinguisher-cylinder colors. that said, a red cylinder is typically associated with which type

Lorico [155]

Fire extinguishers are typically red. Goes along with the red fire trucks and red being a color of emergency. While there isn't any standard, if we decided to change the colors of the fire extinguisher, people would be very confused and given the context, it could cost people's lives, so I'm thinking red will be the color of fire extinguishers for a while to come.
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8 0

2 years ago

Suppose that we use a heater to boil liquid nitrogen (N2 molecules). 4480 J of heat turns 20 g of liquid nitrogen into gas. Note

love history [14]

Answer:

The energy is $9.4\times10^{-21}\ J$