Answer:
The resultant force would (still) be zero.
Explanation:
Before the 600-N force is removed, the crate is not moving (relative to the surface.) Its velocity would be zero. Since its velocity isn't changing, its acceleration would also be zero.
In effect, the 600-N force to the left and 200-N force to the right combines and acts like a 400-N force to the left.
By Newton's Second Law, the resultant force on the crate would be zero. As a result, friction (the only other horizontal force on the crate) should balance that 400-N force. In this case, the friction should act in the opposite direction with a size of 400 N.
When the 600-N force is removed, there would only be two horizontal forces on the crate: the 200-N force to the right, and friction. The maximum friction possible must be at least 200 N such that the resultant force would still be zero. In this case, the static friction coefficient isn't known. As a result, it won't be possible to find the exact value of the maximum friction on the crate.
However, recall that before the 600-N force is removed, the friction on the crate is 400 N. The normal force on the crate (which is in the vertical direction) did not change. As a result, one can hence be assured that the maximum friction would be at least 400 N. That's sufficient for balancing the 200-N force to the right. Hence, the resultant force on the crate would still be zero, and the crate won't move.
Answer:
a. Angular velocity = 0.267rad/s.
b. Centripetal acceleration = 56.25m/s.
Explanation:
<u>Given the following data;</u>
Mass, m = 8kg
Radius, r = 4m
Constant speed, V = 15m/s
a. To find the angular velocity
Angular velocity = radius/speed
Substituting into the equation, we have;
Angular velocity = 4/15
Angular velocity = 0.267rad/s
b. To find the acceleration;
Centripetal acceleration = V²/r
Substituting into the equation, we have;
Centripetal acceleration = 15²/4
Centripetal acceleration = 225/4
Centripetal acceleration = 56.25m/s.
Remember that like charges repel each other. That is, positive repels positive and negative repels negative. Similar to how the north poles of magnets repel each other and south poles repel. However, at the atomic scale, protons, which have positive charge, are more influenced by the "Strong Force," which binds them close together. If they were to be separated ever so slightly, then the electromagnetic force would take over and they would repel each other like you'd expect.
Neutrons are also held together via the Strong Force, but don't have a charge so when separated, don't have an electromagnetic force pushing them away from each other.
However, electrons act differently. There is no "Strong Force" just the electromagnetic force. So, they keep a great distance from each other.
So in an atom, protons and neutrons stay close to each other, taking up little volume, while electrons take up a lot of volume.
BTW, the reason why electrons and protons act differently when they are close together is because protons are made up of smaller particles the carry this Strong Force. For electrons, there is no smaller constituent. And therefore, all you have is the electromagnetic force to influence it. That's it.
Hope that helps.
