Answer:
The mutual speed immediately after the touchdown-saving tackle is 4.80 m/s
Explanation:
Given that,
Mass of halfback = 98 kg
Speed of halfback= 4.2 m/s
Mass of corner back = 85 kg
Speed of corner back = 5.5 m/s
We need to calculate their mutual speed immediately after the touchdown-saving tackle
Using conservation of momentum

Where,
= mass of halfback
=mass of corner back
= velocity of halfback
= velocity of corner back
Put the value into the formula



Hence, The mutual speed immediately after the touchdown-saving tackle is 4.80 m/s
If an object's speed changes, or if it changes the direction it's moving in,
then there must be forces acting on it. There is no other way for any of
these things to happen.
Once in a while, there may be <em><u>a group</u></em> of forces (two or more) acting on
an object, and the group of forces may turn out to be "balanced". When
that happens, the object's speed will remain constant, and ... if the speed
is not zero ... it will continue moving in a straight line. In that case, it's not
possible to tell by looking at it whether there are any forces acting on it.
Answer:
8046.72 meters pretty sure
Answer: No. Circuit should be closed.
Explanation:
A changing magnetic field induces emf in a circuit which is placed in it. This induced emf causes current to flow through it. This is given by Faraday's law which states that induced emf results due to rate of change of magnetic flux.

Current flows only through a closed circuit. Thus, when a wire is moved up and down in a magnetic field, it will not induce emf because the wire does not form a loop. It is an open circuit.
The magnitude of the change in potential energy is equal to the kinetic energy,

or
Here, V is potential difference, q is charge, m is mass and v is velocity.
We can also write,

Given 
Substituting this value with mass of proton,
and charge of proton,
we get

Therefore, the speed of proton is
.