Which is not an example of a scalar? a. 2t/s b. 3kg c. 6.2m north d. -100c

What is the biggest current disadvantage to using gas hydrates as a form of energy?

ohaa [14]

When gas hydrates are brought to the surface, they evaporate quickly. This would be the biggest, current disadvantage to using gas hydrates as a form of energy.

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3 years ago

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A sled is moving down a steep hill. The mass of the sled is 50 kg and the net force acting on it is 20 N. What must be done to f

amid [387]

You need to first measure the angle of descent, i.e. the angle the hill makes with the ground. Then identify the forces acting on the sled, split them up into horizontal and vertical components, or into components that are parallel and perpendicular to the hill, and use Newton's second law to determine the components of the sled's acceleration vector.

There are at least 2 forces acting on the sled:

• its weight, pointing downward with magnitude W = m g

• the normal force, pointing perpendicular to the hill and away from the ground with mag. N

The question doesn't specify, but there might also be friction to consider, indicated in the attachment by the vector F pointing parallel to the slope of the hill and opposing the direction of the sled's motion with mag. F.

Splitting up the forces into parallel/perpendicular components is less work. By Newton's second law, the net force (denoted with ∑ or "sigma" here) in a particular direction is equal to the mass of the sled times its acceleration in that direction:

∑ (//) = W (//) = m a (//)

∑ (⟂) = W (⟂) + N = m a (⟂)

where, for instance, W (//) denotes the component of the sled's weight in the direction parallel to the hill, while a (⟂) denotes the component of the sled's acceleration perpendicular to the hill. If there is friction, you need to add -F to the first equation.

If the hill makes an angle of θ with flat ground, then W makes the same angle with the hill so that

W (//) = -m g sin(θ)

W (⟂) = -m g cos(θ)

So we have

-m g sin(θ) = m a (//) → a (//) = -g sin(θ)

-m g cos(θ) + N = m a (⟂) → a (⟂) = 0

where the last equality follows from the fact that the normal force exactly opposes the perpendicular component of the weight. This is because the sled is moving along the slope of the hill, and not into the air or into the ground.

Then the acceleration vector is

a = a (//)

with magnitude

||a|| = a = g sin(θ).

6 0

3 years ago

Which of the following types of stars is the coolest? In Graph A, the curve peaks at 800 nm, in the red section of the visible l

ASHA 777 [7]

im no scientist but im pretty sure cool stars are warm colors and hot stars are cool colors, so red would be more cooler than blue.

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3 years ago

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Which best describes the motion of air particles when a transverse wave passes through them?

Minchanka [31]

C.
The particles move perpendicular to the direction of the wave.

3 0

3 years ago

In an experiment, a researcher can make claims about causation

Yakvenalex [24]

In an experiment, a researcher can make claims about causation if the independent variable changes because of changes made to the dependent variable. Causation works on cause and effect, so the changed independent variable is the cause and the changed dependent variable is the effect. In an experiment the independent variable is changed to determine the dependent variables value, so the two are directly related.

8 0

3 years ago