The total is 21. If you use a calculator or count with your fingers it can help make the answer easier so in the end you will get 21 as your total.
Using the Planck's Equation, comes:

If you notice any mistake in my english, please let me know, because i am not native.
The equatorial radius of the earth is
r = 6378 km = 6378 x 10³ m
The earth makes 1 revolution in 24 hours.
The angular velocity is
ω = (2π rad)/(24*3600 s) = 7.2722 x 10⁻⁵ rad/s
The tangential velocity (linear velocity) at a point on the equator is
v = rω
= (6378 x 10³ m)*(7.2722 x 10⁻⁵ rad/s)
= 463.8 m/s
Answer: 463.8 m/s
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.
Answer:
66.85 m
Explanation:
We are given that
Acceleration ,a=
Speed of truck, v=9.5 m/s
We have to find the distance beyond which the traffic signal will the automobile overtake the truck.
Initial speed of automobile, u=0
We know that

Using the formula

For constant speed
Acceleration, a=0
Again



Substitute the value of t

Hence, the distance beyond which the traffic signal will the automobile overtake the truck=66.85 m