Answer: 4
Explanation:
Given that:
Mass of car M = 2200 kg
Initial speed Vi = 50 km/hr
Final speed Vf = 100 km/hr
Kinetic energy is the energy possessed by a moving object. It is measured in joules, and depends on the mass (m) of the object and the speed (v) by which it moves
i.e K.E = 1/2MV^2
So, when traveling at 50 km/h
KE = 1/2x 2200kg x (50km/h)^2
KE = 0.5 x 2200 x 2500
KE1 = 2750000J
So, when traveling at 100 km/h
KE = 1/2x 2200 x (100 km/h)^2
KE = 0.5 x 2200 x 10000
KE2 = 11000000J
Thus, the number of times kinetic energy increases is obtained by dividing KE2 by KE1
i.e 11000000J / 2750000J
= 4
Thus, the kinetic energy from the car’s forward motion increase 4 times
A few different ways to do this:
Way #1:
The current in the series loop is (12 V) / (total resistance) .
(Turns out to be 2 Amperes, but the question isn't asking for that.)
In a series loop, the current is the same at every point, so it's
the same current through each resistor.
The power dissipated by a resistor is (current)² · (resistance),
and the current is the same everywhere in the circuit, so the
smallest resistance will dissipate the least power. That's R1 .
And by the way, it's not "drawing" the most power. It's dissipating it.
Way #2:
Another expression for the power dissipated by a resistance is
(voltage across the resistance)² / (resistance) .
In a series loop, the voltage across each resistor is
[ (individual resistance) / (total resistance ] x battery voltage.
So the power dissipated by each resistor is
(individual resistance)² x [(battery voltage) / (total resistance)²]
This expression is smallest for the smallest individual resistance.
(The other two quantities are the same for each individual resistor.)
So again, the least power is dissipated by the smallest individual resistance.
That's R1 .
Way #3: (Einstein's way)
If we sat back and relaxed for a minute, stared at the ceiling, let our minds
wander, puffed gently on our pipe, and just daydreamed about this question
for a minute or two, we might have easily guessed at the answer.
===> When you wire up a battery and a light bulb in series, the part
that dissipates power, and gets so hot that it radiates heat and light, is
the light bulb (some resistance), not the wire (very small resistance).
Answer;
= 312 Newtons
Explanation;
The bullet has a mass of 0.005 kg, and a velocity of 320 m/s, so we need to find it's final kinetic energy.
KE = 1/2*m*v^2
= 1/2*0.005*320^2
= 256 Joules.
Divide this by the distance over which this energy was received and you have the force that provided that energy.
= 256/0.820 = 312.195 Newtons
Rounded off, this is 312 N
We have the relation

where
denotes the velocity of a body A relative to another body B; here I use B for boat, E for Earth, and R for river.
We're given speeds


Let's assume the river flows South-to-North, so that

and let
be the angle made by the boat relative to East (i.e. -90° corresponds to due South, 0° to due East, and +90° to due North), so that

Then the velocity of the boat relative to the Earth is

The crossing is 153.0 m wide, so that for some time
we have

which is minimized when
so the crossing takes the minimum 30.0 s when the boat is pointing due East.
It follows that

The boat's position
at time
is

so that after 30.0 s, the boat's final position on the other side of the river is

and the boat would have traveled a total distance of

Density = (mass) / (volume)
4,000 kg/m³ = (mass) / (0.09 m³)
(4,000 kg/m³) x (0.09 m³) = mass
mass = 360 kg
force of gravity = (mass) x (acceleration of gravity) = (360 kg) x (9.8 m/s²) = (360 x 9.8) kg-m<span>/s² </span><span>= </span>3,528 newtons .