Answer:
Friction acts in the opposite direction to the motion of the truck and box.
Explanation:
Let's first review the problem.
A moving truck applies the brakes, and a box on it does not slip.
Now when the truck is applying brakes, only it itself is being slowed down. Since the box is slowing down with the truck, we can conclude that it is friction that slows it down.
The box in the question tries to maintains its velocity forward when the brakes are applied. We can think of this as the box exerting a positive force relative to the truck when the brakes are applied. When we imagine this, we can also figure out where the static friction will act to stop this positive force. Friction will act in the negative direction. Or in other words, friction will act in the opposite direction to the motion of the truck and box. This explains why the box slows down with the truck, as friction acts to stop its motion.
The independent variable here is the use of diet pills; it was manipulated with the hope of different results
Answer:
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- <em><u>B) Is the solid large enough to be caught by the pores of a filter? </u></em>
Explanation:
An <em>insoluble solid</em> and a <em>liquid</em> form an heterogeneous mixture, meaning the liquid and the solid could be <em>separated</em> by physical media.
If the size of the solid particles are large enough it could be separated from the liquid by filtration.
Since, the task is to separate the mixture into its pure components, the best and first step is to determine whether the solid particles have the size that permit to retain them in the available fliter, which is described by<em> </em>the option <em>B): is the solid large enough to be caught by the pores of a filter? </em>
As for the other options:
<em>A) Is the solid/liquid mixture toxic in its combined form?</em>
- a mixture is not more toxic than its pure components, because they are a physical combination and not a chemical one.
<em>C) Is the melting temperature of the solid lower than that of the liquid?</em>
- you do not want to melt the solid, because that would make the separation more difficult.
<em>D) Can the solid be crushed into smaller particles to allow for distillation? </em>
- crushing the solid will not make it soluble and will not change the boiling point of the solution, thus this is not a step to separate the mixture into its components.
Answer:
9.0 units
Explanation:
The magnitude of the electrostatic force between two charged objects is given by Coulomb's law:
where:
is the Coulomb's constant
are the two charges of the two objects
r is the separation between the two charges
The force is:
- Attractive if the charges have opposite signs
- Repulsive if the charges have same sign
In this probleem, the initial force between the two objects is
F = 18.0 units
Then, the charge of object 1 is halved, so the new charge is
Therefore the new force is
So, the force will also halve: therefore, the new force will be 9.0 units.
There it is written that doubly charged helium particles<span> {</span>alpha particles}<span> were projected onto very thin gold foil. Most of the </span>alpha particles<span> passed straight through, but some of the </span>alpha particles bounced back<span> because positive </span>particles {<span>protons} in the nucleus repelled them.</span>