This is very good conceptual question and can clear your doubts regarding work-energy theorem.
Whenever force is perpendicular to the direction of the motion, work done by that force is zero.
According to work-energy theorem,
Work done by all the force = change in kinetic energy.
here, work done = 0.
Therefore,
0=change in kinetic energy
This means kinetic energy remains constant.
Hope this helps
Need to draw it first.....
but there is no option here to draw .. why?
anyway , here the car is going with a uniform velocity..
so the acceleration of the car=0, a=0
so resistive force on the car=component along the inclined plane of the weight of the car=mg*cos(90-15)=960*9.8*cos 75=?
Answer:
Explanation:
A fire alarm notification appliance is an active fire protection component of a fire alarm system. The primary function of the notification appliance is to alert persons at risk.
If want the audible public mode signal to be hear clearly then, we need to have a sound level that is at least 15dB above the average ambient sound level or 5dB above the maximum sound level of at least 1minute
In this case the,
The average ambient sound level is 62dB,
And the maximum sound level is 68dB
Then, the public mode signal should be at least
1. 62dB+ 15dB=77dB
Or
2. 68dB +5dB =73dB.
Then the public mode signal hearing must be at least 77dB.
It acts in the upward direction.
The bigger the mass of an astronomical object the bigger the depression it causes in the space-time fabric. Any other astronomical object that gets closer to this depression begins to fall into the depression and hence accelerates closer to the astronomical object causing the depression. This is how gravity is felt.
