It means that you note down the observation at time t = t1 of some experiment which you are performing.
Answer:
Slowing a bike by applying the brkaes is an xmaple of acceleration
Explanation:
In physics, displacement is a physical quantity that is used to describe the overall change in the position of an object/person.
In other words, it describes how far you are from your initial position.
In the given problem, the initial position is the same as the final position. This means that overall change in position is zero, which also means that the difference between the final and initial positions is zero.
Based on the above, the displacement is zero.
Jenny is traveling southward. In order to stop, she needs a northward acceleration.
A better way to say it:
Jenny is traveling southward in her bumper car, so the direction of her velocity is south. In order to reduce her velocity to zero, a velocity of equal magnitude but directed north must be added to it. Then the change in velocity is positive northward, and the change in velocity per unit time is acceleration.
Answer:

Explanation:
From the question we are told that
Nucleus diameter 
a 12C nucleus
Required kinetic energy 
Generally initial speed of proton must be determined,applying the law of conservation of energy we have

where
=initial kinetic energy
=final kinetic energy
=initial electric potential
=final electric potential
mathematically

where
=distance b/w charges
=nucleus charge 
=constant
=proton charge
Generally kinetic energy is know as

Therefore
Generally equation for radius is 
Mathematically solving for radius of nucleus


Generally we can easily solving mathematically substitute into v_1









Therefore the proton must be fired out with a speed of 