Answer:
54mph
Explanation:
Speed is defined as the change in distance of a body with respect to time.
Let x be the speed of Eric on his way to the football game, if he used 11hours to the football game, his distance will be the product of his speed and time taken i.e
Distance = speed × time
Distance= x × 11
Distance = 11x... (1)
During his return journey, his speed increases by 12mph with a return drive in only 9hours i.e speed = x+12 and time is 9hours
Since distance = speed × time (return Journey)
Distance = (x+12)×9
Distance = 9x+84...(2)
Note that the distance to and fro the journey is the same as such we will equate equations 1 and 2 to get his initial speed "x" to have;
11x = 9x+84
11x-9x = 84
2x = 84
x = 42mph
This means that his initial speed on his way to the football game is 42mph. Since his speed increases by 12mph during his return drive, his return speed will be 42mph + 12mph which gives 54mph.
The answer is B- a positive charge
This is more along the lines of "Does gravity affext potential energy"
Sort of. Potential energy is an odd one to imagine, sometimes.
It's the energy possessed by an object or system by dint of it's spatial
and mechanical configuration.
That definition alone is perhaps not so useful...and it's certainly not
official. But what it means is that an object can potentially have
energy due to where it is or what state the system is in.
Imagine we have a box and it's on the floor. The box, for all intents
and purposes, has no potential energy. It isn't going anywhere and it
just sits on the floor. It can't do any work in it's current position.
Now we hoist the box into the air. For any distance the box travels from
the floor, it gains potential energy. Now let's back track. We've
changed the box's spatial configuration by hoisting it into the air and
so have given it potential energy.
Why does it now have potential energy? Because we can now drop the box
(costing us no energy) and the box will fall. Maybe it falls onto a
passer-by and injures them.
Box on the floor = No energy.
We lift the box = We spend our energy and give the box potential energy
(as it wants to fall toward the ground).
We drop the box = Potential energy is converted to kinetic energy as the
box falls.
Box injures someone = The kinetic energy has done work upon the person.
So we can see how it all flows and connects. We have to put energy into
the box to fight against gravity, but you can't destroy or create
energy....so the energy we've spent is potentially stored 'inside' the
box.
Clearly, gravity effects a LOT of potential energies around us. In fact
to some small extent, it's probably impossible to entirely avoid it's
effects.
Answer:
The ball rolled a distance of 54 m.
Explanation:
Given:
Initial velocity of the ball is, 
Final velocity of the ball is, 
Time for rolling is, 
The distance of rolling is, 
First, let us find the acceleration of the ball using Newton's equation of motion as:
Now, displacement of the ball can be determined using the following equation of motion:
Rewriting the above in terms of 'S', we get
Plug in the known values and solve for 'S'. This gives,
Therefore, the ball rolled a distance of 54 m.
