Answer:
The net force is zero, so the acceleration is zero
Explanation:
Newton's second law states that the acceleration of an object is proportional to the net force applied to it, according to the equation:
(1)
where
is the net force on the object
m is the mass of the object
a is its acceleration
In this problem, we have a sled acted upon two forces, 
. So the net force on the sled is
(2)
however, we are told that the two forces are equal in magnitude but in opposite directions, so
So, eq.(2) becomes
and so eq.(1) becomes
which means
so the acceleration of the sled is zero, and if the sled was at rest, it will not move.
Answer:
decreases by a factor of 4
Explanation:
Lets take mass of the objects are m₁ and m₂ and the distance between them at initial condition is R.
We know that attraction force between two object given as
G=Constant
If distance become 2 R
R' = 2R
Therefore we can say that gravitational force will become one forth of the initial force.
"
Hybrids come in various different flavors. In parallel hybrids, the engine and
the motor both send power to the wheels; in series hybrids, only the
motor powers the wheels, while the engine simply drives the motor like a generator, recharging the batteries.
Full hybrids have powerful enough electric motors and batteries to drive the engine
independently, while in mild hybrids, the motor is too puny to power the car by itself
and simply assists the engine (or allows it to switch off when the car is idle in traffic).
Ordinary hybrids charge up their batteries using power from the
engine and energy recovered from the regenerative brakes (which we'll
come onto in a moment); plugin hybrids can also be "refueled" from a
charging station or domestic power supply, have much bigger batteries, and can be driven by the motor
and batteries alone, so work more like conventional electric cars.
Whatever the coupling of engine and motor, the basic idea is to combine
the best of both worlds to
boost fuel economy. The big drawback of a hybrid is that its around
20–30 percent more expensive than a comparable gasoline model. It's
likely to be 10 percent heavier
(despite its lighter engine, it has an electric motor, batteries,
regenerative brakes, and all the rest) and have more sluggish
performance. But hybrids score far better on both safety and fuel
economy than gasoline cars, which makes them popular with eco-conscious
families who prize their green credentials." - http://www.explainthatstuff.com/electriccars.html I hope this helps!
