Answer:
The average speed of a car is 20 km/h.
Explanation:
We have,
Distance covered by car is 10 km
Time taken by the car to cover that distance is 30 min. 30 min means 0.5 hours.
It is required to find the average speed of a car. It can be calculated using formula of average speed which is given by :

So, the average speed of a car is 20 km/h.
Answer:

Explanation:
The acceleration due to gravity on the surface of the Earth is given by:

where
G is the gravitational constant
M is the mass of the Earth
R is the radius of the Earth
Here we want to find the new Earth radius R' for which the gravitational acceleration at the surface, g', would be 3 times the current value of g:

So we would have

Solving the equation for R', we find

Answer:
Explanation:Digestive juices secreted by various organs such as salivary glands in the mouth, stomach, liver and pancreas help in the process of digestion of food. Saliva secreted by the salivary glands in the mouth aids in the breakdown of starch present in the food to simple sugar
1) using kirchhoff voltage and current law.
2) voltage and current divider rule
3) ohm's law
Answer:
408.25 Hz.
Explanation:
The fundamental frequency of a stretched string is given as
f' = 1/2L√(T/m') .................... Equation 1
Note: The a steel piano wire is a string
Where f' = fundamental frequency of the wire, L = length of the wire, T = tension on the wire, m' = mass per unit length of the wire.
Given: L = 0.4 m, T = 800 N,
Also,
m' = m/L where m = mass of the steel wire = 3.00 g = 3/1000 = 0.003 kg.
L = 0.4 m
m' = 0.003/0.4 = 0.0075 kg/m.
Substituting into equation 1
f' = 1/(2×0.4)[√(800/0.0075)]
f' = 1/0.8[√(106666.67)]
f' = 326.599/0.8
f' = 408.25 Hz.
Hence the frequency of the fundamental mode of vibration = 408.25 Hz.