Answer
given,
mass of the ball = 3 kg
swing in vertical circle with radius = 2 m
work done by the gravity = ?
work done by the tension = ?
Work done by the gravity = - m g Δh
Δ h = 2 + 2 = 4 m
Work done by the gravity =
= -117.6 J
work done by gravity is equal to -117.6 J
Work done by tension will be equal to zero.
Zero because tension is always perpendicular to velocity
work done by tension is equal to 0 J
Hope this is helpful <span>Weightlessness
</span>
Answer:
Expression of work done is

Work done to move the sled is given as 1.94 J
Explanation:
As we know that the formula of work done is given as

here we know that
F = 6 N
d = 0.4 m

so we will have


The heat required to convert the unknown substance X from one phase to another is 1600 J times the specific heat of that substance.
Explanation:
The heat energy required to convert a substance or to heat up or increase the temperature of a substance can be obtained from the specific heat formula.
As per this formula, the heat energy applied should be equal to the product of mass of the substance with temperature gradient and also with specific heat of the substance. Basically, the heat provided to increase or convert a substance should be more than the specific heat of the substance.

Since, here the mass of the substance X is given as m = 20g and the temperature change is given from -10°C to 70°C.
Then ΔT = (70-(-10))=70+10=80°C.
As the substance is unknown, the specific heat of that substance can also not be determined. Hence keep it as C.

Q = 1600C J
Thus, the heat required to convert the unknown substance X from one phase to another is 1600 J times the specific heat of that substance.
Kinetic energy<span> is the </span>energy<span> of motion. An object that has motion - whether it is vertical or horizontal motion - has </span>kinetic energy<span>. It is expressed as:
KE = mv^2 /2
720 = 10.0v^2 /2
v = 12 m/s
Hope this answers the question. Have a nice day.</span>