Answer:
It's A
Explanation:
As the waves progress through the medium, the particles they are made of move perpendicular to the direction in which the waves move. The particles do not move with the wave. So waves transmit energy but not matter as they progress through a medium.
When light passes from one medium to another, part of it continues on
into the new medium, while the rest of it bounces away from the boundary,
back into the first medium.
The part of the light that continues on into the new medium is <em>transmitted</em>
light. Its forward progress at any point in its journey is <em>transmission</em>.
Its direction usually changes as it crosses the boundary. The bending is <em>
refraction</em>.
The part of the light that bounces away from the boundary and heads back
into the first medium is <em>reflected</em> light. The process of bouncing is <em>reflection</em>.
2.0 meters The skateboarder has 2 forces acting upon him to slow him down. The forces are friction, and climbing against the gravitational acceleration. So let's calculate the magnitude of these forces to see how fast he's decelerated. The coefficient of kinetic friction is a multiplier to use against the normal force of the object. We can calculate the normal force by multiplying the mass of the object by the local gravitational acceleration and the cosine of the angle. So Df = 60 kg * 9.8 m/s^2 * cos(20°) * 0.30 Df = 60 kg * 9.8 m/s^2 * 0.939692621 * 0.30 Df = 60 kg * 9.8 m/s^2 * 0.939692621 * 0.30 Df = 165.7617783 kg*m/s^2 Df = 165.7617783 N
The second amount of force is that caused by gravitational acceleration while climbing. That is determine by the amount of height gained for every meter along the slope. We can calculate that using the sine of the angle. So
Dg = 60 kg * 9.8 m/s^2 * sin(20°)
Dg = 60 kg * 9.8 m/s^2 * 0.342020143
Dg = 201.1078443 kg*m/s^2
Dg = 201.1078443 N
So the amount of force decelerating the skateboarder is:
F = Df + Dg
F = 165.7617783 N + 201.1078443 N
F = 366.8696226 N
Now let's determine how much kinetic energy needs to be dissipated. The equation is
E = 0.5 MV^2
So we'll substitute the known values and calculate
E = 0.5 MV^2
E = 0.5* 60 kg * (5 m/s)^2
E = 0.5* 60 kg * 25 m^2/s^2
E = 750 kg*m^2/s^2
E = 750 J
Now let's divide the energy by the force.
750 kg*m^2/s^2 / 366.8696226 kg*m/s^2 = 2.04432298 m
Rounding to 2 significant figures gives a distance of 2.0 meters.
<h3>1)</h3>
No,kinetic energy cannot be negative since its given by KE=mv²,mass cannot be negative and the square of speed cannot b negative.
<h3>2)</h3>
Yes,any force opposing motion or displacement does negative work. They are often referred to as resistive forces (friction,air resistance,drag...)
<h3>3)</h3>
Nope it does not, it just forces the object to move in a circular path known as a centripetal force. It can accelerate an object by changing it's direction but not it's speed.
<h3>4)</h3>
No it cannot,If an object is sliding on the table (assuming it is not an incline), then most probably that normal force cancels out the weights effect or assuming there is an incline, it cancels the weight's y component.
<h3>5)</h3>
The work done is zero
<h3>6)</h3>
The work is just the product of the magnitude of the force exerted and the displacement of the object.
<h3>7)</h3>
<h3>Work is decreasing but positive</h3>
<h3>8)</h3>
<h3>Work is zero</h3>
<h3>9)</h3>
<h3>Work is negative</h3>
<span>A unicellular organism, also known as a single-celled organism, is an organism that consists of only one cell, unlike a multicellular organism that consists of more than one cell.</span>
