Answer:
The net force is 1350 kN
Solution:
As per the question:
Mass of man, m = 60 kg
Initial speed of the car, v = 15 m/s
Final speed of the car, v' = 0 m/s
Distance covered by the person before coming to rest, d = 5 mm = 
By using the third eqn of motion:



Thus the force on the person can be given by:
F = ma = 
Answer:
A change in the size of the population may bring about changes in the culture. For example, food brought to this country by immigrant groups have become common in many American kitchens. Population increases and decreases affect the economy. For example, by increasing the demand for goods and services, a growing population may increase employment and stimulate the economy. An increase in the general population also means that there are more people occupying the same amount of space, which creates more crowded conditions. In addition, the larger population brings increased demand for energy, food, housing, schools, stores, and transportation. People also bring about changes simply by moving from one place to another. Migrations of people within a country can cause social changes, such as the loss of regional distinction within the country. Social and cultural changes also result from changes in the average age of a population. When fewer people are having babies, for example, there is less need for schools, recreation centers, and other services geared toward children.
The problem is basically asking us to find a way to find the sound intensity I, in terms dependent on the sound level and the reference intensity
.For this purpose we can start from the unit used in the scale logarithmic decibel, that is

Where
I = Acoustic intensity on the linear scale
Hearing threshold
Using the logarithmic properties of the exponents the above expression can be described as:

that is the expression or technique to find the intensity of sound.
Answer:
Speed of both blocks after collision is 2 m/s
Explanation:
It is given that,
Mass of both blocks, m₁ = m₂ = 1 kg
Velocity of first block, u₁ = 3 m/s
Velocity of other block, u₂ = 1 m/s
Since, both blocks stick after collision. So, it is a case of inelastic collision. The momentum remains conserved while the kinetic energy energy gets reduced after the collision. Let v is the common velocity of both blocks. Using the conservation of momentum as :



v = 2 m/s
Hence, their speed after collision is 2 m/s.