Answer:
reflection is the act of reflecting or the state of being reflected while echo is
reflection of sound waves from a surface back to the initial listener
Complete Question
Use Stefan's law to find the intensity of the cosmic background radiation emitted by the fireball of the Big Bang at a temperature of 2.81 K. Remember that Stefan's Law gives the Power (Watts) and Intensity is Power per unit Area (W/m2).
Answer:
The intensity is 
Explanation:
From the question we are told that
The temperature is 
Now According to Stefan's law
Where 
is the Stefan Boltzmann constant with value 
Now the intensity of the cosmic background radiation emitted according to the unit from the question is mathematically evaluated as
=> 
=> 
substituting values
Without friction, we would not be able to stop walking since we would just keep slipping like on ice.
Without friction, objects would just slip and fall with a simple blow of air
And finally without friction we wouldn't be able to use machinery like cars and etc since they would just fly off
Hope this helps!
(tell me if im right)
Answer: The bell has 8550 J energy.
given, There is a bell at the top of a tower that is 45 m high. The bell weighs 190 N
i.e., bell is located at the top of tower, h = 45m
weight of the bell, F = 190 N
workdone by the gravitational force = F.hcos180°
[ gravitational force (i.e., weight ) acting downward while body is located 45m above the ground. so, angle between force and h = 180° ]
workdone by the gravitational force = 190 × 45 × (-1)
= -8550 J
we know, potential energy = negative of workdone
= -(-8550 J) = 8550 J
A ramp is a smooth incline that allows an object to be lifted without being lifted directly up. therefore, an inclined plane is the correct answer.
