Answer:
1.2ms⁻²
Explanation:
F = ma
12 = 10*a
12/10 = a
6/5 ms⁻² = a or 1.2 ms⁻² = a
Added potential energy = (mass) x (gravity) x (height)
or
Added potential energy = (weight) x (added height)
If you need to lift a 15N box 3m straight up, you have to increase its potential energy by (15 N) x (3 m) = 45 Joules .
Where is that added potential energy supposed to come from ? You could use an electric winch, a steam engine, a gasoline-powered motor, thousands of hamsters running on little treadmills that are are connected to the main pulley somehow, or your own arm muscles. But howEVER you do it, you have to provide <em>45 Joules</em> of WORK in order to increase the potential energy of the box by just that much.
Answer:
It can go back to it's original shape
Explanation:
Answer:
greater than your true weight
Explanation:
When going up in an elevator the acceleration of the elevator is added to the acceleration due to gravity. This will increase the reading on the scale.
The expression of the resultant weight will be

where,
m = Mass of the person
g = Acceleration due to gravity = 9.81 m/s²
a = Acceleration of the elevator.
Hence, the reading on the scale is <u>greater than your true weight.</u>
The distance covered by car is equal to (assuming it is moving by uniform motion) the product between the car's speed and the time of the car ride, 4 h:

where

is the car's speed

is the duration of the car ride
Similarly, the distance covered by train is equal to the product between the train's speed and the duration of the train ride, 7 h:

The total distance covered is S=255 km, which is the sum of the distances covered by car and train:

which becomes

(1)
we also know that the train speed is 5 km/h greater than the car's speed:

(2)
If we put (2) into (1), we find

and if we solve it, we find


So, the car speed is 20 km/h and the train speed is 25 km/h.