Answer:
2.61 J
Explanation:
Since potential energy U = mgy where m = mass of object, g = acceleration due to gravity = 9.8 m/s² and y = height of object above the ground.
Now for the coffee mug, m= 0.422 kg and it is 0.63 m on a table, so it is 0.63 m above the ground. Thus, y = 0.63 m.
We compute U
U = mgy
= 0.422 kg × 9.8 m/s² × 0.63 m
= 2.605 J
≅ 2.61 J
So, the potential energy of the mug with respect to the floor is 2.61 J
Answer:
Lifting force, F = 21240 N
Explanation:
It is given that,
Mass of the helicopter, m = 1800 kg
It rises with an upward acceleration of 2 m/s². We need to find the lifting force supplied by its rotating blades. It is given by :
F = mg + ma
Where
mg is its weight
and "ma" is an additional acceleration when it is moving upwards.
So, 
F = 21240 N
So, the lifting force supplied by its rotating blades is 21240 N. Hence, this is the required solution.
Answer:
C. CT
Explanation:
It stands for Computed Tomography Scans.
If both waves have the same wavelength, then the amplitude of
their sum could be anything between 1 cm and 9 cm, depending
on the phase angle between them.
If the waves have different wavelengths, then the resultant is a beat
with an amplitude of 9 cm.
The ball can't reach the speed of 20 m/s in two seconds, unless you THROW it down from the window with a little bit of initial speed. If you just drop it, then the highest speed it can have after two seconds is 19.6 m/s .
If an object starts from rest and its speed after 2 seconds is 20 m/s, then its acceleration is 20/2 = 10 m/s^2 .
(Gravity on Earth is only 9.8 m/s^2.)
