Answer:
Wg is positive and WT negative.
(Letters in options are all wrongly written).
Explanation:
Remember that the work of a force is the internal product between the force and the displacement .
Since the displacement is downwards like the weight, the work done by gravity is positive, while the work done by the tension is negative since it points upwards.
Answer:
The mass of the 500 series bullet train is 181.4 tonnes.
Explanation:
The momentum is given by:
Where:
m: is the mass =?
v: is the velocity = 261.8 km/h
p: is the momentum = 13194098.64 kg*m/s
By solving the above equation for "m" we have:
Therefore, the mass of the 500 series bullet train is 181.4 tonnes.
I hope it helps you!
Answer:
The kinetic energy is: 50[J]
Explanation:
The ball is having a potential energy of 100 [J], therefore
PE = [J]
The elevation is 10 [m], and at this point the ball is having only potential energy, the kinetic energy is zero.
In the moment when the ball starts to fall, it will lose potential energy and the potential energy will be transforme in kinetic energy.
When the elevation is 5 [m], we have a potential energy of
This energy is equal to the kinetic energy, therefore
Ke= 50 [J]