Answer:
Explanation:
The stunt will likely sustain serious injury in case of concrete blocks because the average force acting on the person will be more because concrete blocks do not squeeze to provide more time for the force to act on the body instead it acts for a small amount of interval.

As impulse is constant so time requires to act force on the body is more as compared to concrete block and thus average force in mattress case is less.
Explanation:
The equation of motion of an object is given by :

Where
t is the time in seconds
We need to find the time when the object hits the ground. When the object hits the ground, h(t) = 0
So,


On solving above equation using online calculator, t = 8 seconds. So, the object hit the ground after 8 seconds. Hence, this is the required solution.
Answer: A, C, E
Explanation:
Gamma rays, Microwaves, and Radio waves
Part a)
per day electricity power consumed when 100 W bulb is used for 8 hours

for one year consumption

now the cost will be given

now when other energy efficient light is used

for one year consumption

now the cost will be given

Answer:
<h3>The answer is option B</h3>
Explanation:
The frequency of a wave can be found by using the formula

where
c is the velocity
From the question
wavelength = 0.39 m
c = 86 m/s
We have

We have the final answer as
<h3>200 Hz</h3>
Hope this helps you