The correct option is A.
Fluorescent lamps have many advantages over incandescent lamps and the options given in B, C and D are part of these advantages. The option given in A is a disadvantage and not an advantage. This is because, as a result of operating at an higher temperature, it will gives out and radiate more heat.
Answer:
The object starts away from the origin and then moves toward the origin at a constant velocity. Next, it stops for one second. Finally, it moves away from the origin at a greater constant velocity.
Answer:
Object will float.
Explanation:
Total force on the body = Weight of body + Buoyancy force on body.
Weight of body = 15 N downwards = 15 N
Buoyancy force on body = 17 N upwards = -17 N
Total force on body = 15 - 17 = -2 N = 2 N upwards
So, the body will float.
Object will float.
Answer:
The speed of the roller coaster at this point is 18.74 m/s.
Explanation:
Given that,
Weight of the student, W = 655 kg
Weight of the roller coaster, 
Radius of the roller coaster, r = 18 m
At the bottom of the loop, the weight of the roller coaster us given by :

If m is the mass of the roller coaster,



m = 66.83 kg
So,



v = 18.74 m/s
So, the speed of the roller coaster at this point is 18.74 m/s. Hence, this is the required solution.