Answer:
4.0 m/s
Explanation:
The motion of the diver is the motion of a projectile: so we need to find the horizontal and the vertical component of the initial velocity.
Let's consider the horizontal motion first. This motion occurs with constant speed, so the distance covered in a time t is

where here we have
d = 3.0 m is the horizontal distance covered
vx is the horizontal velocity
t = 1.3 s is the duration of the fall
Solving for vx,

Now let's consider the vertical motion: this is an accelerated motion with constant acceleration g=9.8 m/s^2 towards the ground. The vertical position at time t is given by

where
h = 4.0 m is the initial height
vy is the initial vertical velocity
We know that at t = 1.3 s, the vertical position is zero: y = 0. Substituting these numbers, we can find vy

So now we can find the magnitude of the initial velocity:

They were going at a velocity 4.07m/s
<u>Explanation:</u>
Distance s =5 m
initial velocity u= 0.8 m/s
Acceleration a =1.6m/s2
We have to calculate the velocity with which they were going afterwards i.e final velocity.
Use the equation of motion

They were going with a velocity 4.07 m/s afterwards.
Answer:
Efficiency of wedge is the ratio of "work done by the machine to the work supplied to the machine".
Efficiency (η) = Work done by machine ÷ Work supplied
= 65 ÷ 75
= 0.86%
<em>Efficiency of wedge is 86%</em>
Answer:
True.
Explanation:
Total internal reflection is bound to occur when light travels from dense medium to less dense.
From the table given in the question above, we obtained:
Refractive Index of Crown glass = 1.52
Refractive Index of Asphalt = 1.635
From the above, Crown glass has a lower refractive index when compared to Asphalt. This means that Crown glass is less dense than Asphalt.
Therefore, total internal reflection will not occur when light travels from Crown glass to Asphalt because Crown glass is less dense than Asphalt.