Answer: because the air currents move upwards so the hot air fills up the whole room. Similarly if the air conditioner is placed neer the ceiling because it gives cool air
Answer:
The normal force the ground exerts on the block, F = -300 N
Explanation:
Given data,
The block pulled up with a tension force, T = 100 N
The weight of the block, W = 300 N
The weight of the block is due to the force of attraction of gravitation.
The surface exerts a force that is equal and opposite to the force acting on the block due to gravitation.
The weight of the block,
W = mg
300 N
The normal force the ground exerts on the block,
F = - mg
= - 300 N
Hence, the normal force the ground exerts on the block, F = -300 N
Answer:
13 km/h
Explanation:
Average speed = distance/time
Let the total distance and total time taken for the whole trip be d km and t hours respectively
Average speed for the whole trip = 82 km/h
d = 82t
The distance covered in the first half = d1/2
Time taken = t/2
Average speed = 69 km/h
69 = d1/2 ÷ t/2
d1 = 69t
The distance covered in the second half = d2/2
Time taken = t/2
Let the average sly for the see half be A
A = d2/2 ÷ t/2
d2 = At
d = d1 + d2
82t = 69t + At
At = 82t - 69t
At = 13t
A = 13t/t = 13 km/h
To solve the problem it is necessary to apply the concepts related to sound intensity. The most common approach to sound intensity measurement is to use the decibel scale:
Where,
is a reference intensity. It is the lowest or threshold intensity of sound a person with normal hearing can perceive at a frequency of 1000 Hz.
I = Sound intensity
Our values are given by,
For each auto the intensity would be,
Therefore the sound intesity for the 7 autos is
The sound level for the 7 cars in dB is
Balanced Forces acting on an object will not change the object's motion. Unbalanced Forces acting on an object will change the change the object's motion.
