Answer:
option d) -9 J
Explanation:
Given:
Mass, m = 3.0 kg
time, t = 6.0 seconds
Velocity of mass, v = 2.0 m/s
height, h = 2 m
Now, using the concept of work-Energy theorem
we have
Net work done = change in kinetic energy
or
Work done by gravity + work done by the friction = Final kinetic energy - Initial kinetic energy
mgh +
= 
on substituting the values in the above equation, we get
3 × 9.8 × 2 + = 
or
58.8 + = 6
or
= -52.8 J
here negative sign depicts that the work is done against the motion of the mass
also,
Power = (Work done)/time
or
Power = -52.8/6 = -8.8 W ≈ 9 J
Hence, option d) -9 J is correct
This is best explained through the use of an optics diagram, this is a little too complicated to explain in a short answer, and as I can't draw an appropriate diagram in this answer, I will point you to this excellent resource which explains what you have asked very well!
Go onto the BBC website (you should have access to it even if you aren't in the UK) and paste this after the BBC url,
/bitesize/intermediate2/physics/waves_and_optics/image_formation_from_lens/revision/1/
<span>We know that pressure is the force applied into a surface, in our case the wall of the room, so then first we will calculate the surface of this wall:
S = 2.2 * 3.2 = 7.04 m2
Then we also know the atmospheric pressure in normal conditions is 1 atm. That is the same 1 atm = 101325 Pascals or 101325 N/m2
Now we need to use the formula : P = F/S where P is pressure, F is force and S is surface to calculate the force:
F = P * S = 101325 * 7.04 = 713,328 Newtons
Conclusion: the force acts on the wall due the air inside the room is 713,328 N</span>
Answer: Option (c) is the correct answer.
Explanation:
Language is defined as a medium through which a person can deliver its thoughts, ideas, or perceptions to one or more individuals.
For example, Leslie is feeling sad and that is why she is crying. Therefore, listening a cry sound her friend sitting in the next room came immediately to console her.
Hence, sound of crying is also a sign of language that tells Leslie is sad about something.
Therefore, we can conclude that the statement languages use spoken sounds, written words, and signs to represent ideas and events, is true about language.
Answer:
Explanation:
F = ma and
We have F, we have m, but in order to solve for v, we need a.
30.0 = 3.00a so
a = 10.0 m/s/s. Plug that in for a in the second equation and solve for v:
so
v = 10.0(3.00) so
v = 30.0 m/s
