Because if there's no force on the object, then it just moves in a straight line.
Answer:
<em>a. The molecules of solid are closely packed together</em>
<em>b. particles are so close, hence a high density</em>
<em>c.rate of diffusion is slow due to strong force of attraction between molecules of solid.</em>
Explanation:
(a)The molecules of solids are very much packed together hence very hard to compress and the force of attraction between molecules is strong hence very hard to expand . For this reason solids occupy a definite volume.
b. Because the molecules of solid is more closer than those of liquid and gas. Solids have a much higher density, hence a higher relative density. Density = mass/volume. for solids a huge amount of mass occupies a low volume space. A low volume and huge mass will result in high density
c. The diffusion of solids is very slow due to the strong force of attraction between the molecules of solids. However this diffusion can be made faster by the application of heat. This will increase the kinetic energy of the solid molecules.
Kinetic is something moving and potential is being still
Momentum of an object is calculated by multiplying the mass by the velocity.
p = mv
where:
p = momentum
m = mass
v = velocity
Let's take your given into account and put it in the equation:
p = mv
30,000 kg.m/s = (400kg)v
Velocity is our unknown, so to get it all we need to do is transfer mass (m) to the other side of the equation and isolate the velocity (v). When we do this, we need to use the opposite operation (rules of transposition).
(30,000kg.m/s)/(400kg) = v
Cancel out the kg and you are left with m/s.
75m/s = v
The answer is then D. 75 m/s.
Now for your second question, as you can see in the formula, mass and velocity is directly proportional to momentum. That means that the higher the mass or the velocity, the higher the momentum.
So if the velocity increases, the momentum increases as well.
