in which phase change does a substance change from a solid to a gas vapor without changing to a liquid first?

In the design of a supermarket, there are to be several ramps connecting different parts of the store. Customers will have to pu

tatuchka [14]

Answer:

3.90 degrees

Explanation:

Let g= 9.81 m/s2. The gravity of the 30kg grocery cart is

W = mg = 30*9.81 = 294.3 N

This gravity is split into 2 components on the ramp, 1 parallel and the other perpendicular to the ramp.

We can calculate the parallel one since it's the one that affects the force required to push up

F = WsinΘ

Since customer would not complain if the force is no more than 20N

F = 20

$294.3sin\theta = 20$

$sin\theta = 20/294.3 = 0.068$

$\theta = sin^{-1}0.068 = 0.068 rad = 0.068*180/\pi \approx 3.90^0$

So the ramp cannot be larger than 3.9 degrees

6 0

3 years ago

What would be an example of a chemical change that took a long time to occur

weqwewe [10]

<span>rusting takes a long time, and rusting is a chemical change</span>

3 0

3 years ago

Read 2 more answers

Describe the results of Ernest Rutherford's gold-foil experiment and explain how his results changed ideas about the distributio

DochEvi [55]

In Rutherford's gold foil experiment, some of the positive particles would pass through the foil and some would bounce off. This led to a new theory that all of the positive subatomic particles were in the center of the atom instead of evenly spread throughout.

4 0

3 years ago

At what speed do a bicycle and its rider, with a combined mass of 100 kg, have the same momentum as a 1400 kg car traveling at 6

Ilia_Sergeevich [38]

Momentum of car

Given: Mass m= 1,400 Kg; V = 6.0 m/s

Formula: P = mv

P = (1,400 Kg)(6.0 m/s)

P = 8,400 Kg.m/s

Velocity of the rider to have the same momentum as a car.

Mass of rider and bicycle m = 100 Kg

P = mv

V = P/m

V = 8,400 Kg.m/s/100 Kg

V = 84 m/s

7 0

3 years ago

Jill does twice as much work as Jack does and in half the time. Jill's power output is Group of answer choices one-fourth as muc

Musya8 [376]

Answer:

Second Choice.

Explanation:

Jack's Power = W/t

Jill's Power = 2W/(0.5)*t

2/0.5 = 4

Jill's Power = 4*W/t

Jill's Power is 4 times greater than Jack's

Second Choice

3 0

2 years ago