Answer:
The instantaneous speed of the object after the first five seconds is 12.5 m/s.
(C) is correct option.
Explanation:
Given that,
An object starts at rest. Its acceleration over 30 seconds.
We need to calculate the instantaneous speed of the object after the first five seconds
We know that,
Area under the acceleration -time graph gives speed.
According to figure,
Hence, The instantaneous speed of the object after the first five seconds is 12.5 m/s.
Answer:
sometimes harmful and sometimes beneficial
Answer:
The speed of the shell at launch and 5.4 s after the launch is 13.38 m/s it is moving towards the Earth.
Explanation:
Let u is the initial speed of the launch. Using first equation of motion as :
a=-g
The velocity of the shell at launch and 5.4 s after the launch is given by :
So, the speed of the shell at launch and 5.4 s after the launch is 13.38 m/s it is moving towards the Earth.
Answer:
194516 sheets
Explanation:
So the area of each sheet of paper is:
A = 0.216 * 0.279 = 0.060264 square meters
For the paper sheet to make the same effect as the atmospheric pressure P, then the gravity F from the paper sheet must be
F = AP = 0.060264 * 101325 = 6106 N
Let g = 9.81 m/s2, then the mass of paper needed to generate that gravity is
m = F/g = 6106 / 9.81 = 622.4 kg
If each sheet has a mass of 0.0032 kg, then the total number of sheets to have that much mass is
622.4 / 0.0032 = 194516 sheets
As the surface given is a smooth surface, we can use specular reflection. According to the law of specular reflection, the angle of incidence equals the angle of reflection, so it will also be 40°. Answer is A.
