The dummy's acceleration is 11 m/s^2
(also known as 11 meters per sec. per sec.)
a = F/m
= 825 N/75 kg
= 11 m/s^2
Answer
F = 124 N
Explanation:
given,
mass, m = 5 Kg
time, t = 4.1 s
displacement = y(t)=(2.80 m/s)t +(0.61 m/s³)t³
velocity


again differentiating to get the equation of acceleration


force at time t = 4.10 s
F = m a
F = 5 x 3.66 x 4.1
F = 75 N
the net force when crate is moving upward
F = Mg + Ma
F = 5 x 9.8 + 75
F = 124 N
the magnitude of force is equal to 124 N
Answer:
the correct one is the third :
can travel through a region void of matter and mechanical waves cannot
Explanation:
Mechanical waves travel supported by a material medium, for example sound waves travel in air, the wave on a string travels on the string.
Electromagnetic waves are produced by the variation of electric and magnetic fields, after producing this variation by the lenz law the variation of one field induces the other, so these waves do not need a material medium to travel.
Of the final statements the correct one is the third :
can travel through a region void of matter and mechanical waves cannot
Answer:

Explanation:
we use the equation for the final speed:

where
is the final speed,
is the initial speed,
is the gravitational acceleration (
) and
is the height.
In this case we don't have an initial velocity indicated so:
, and we are told that the boulder is at a height:
.
We substitute this values into the equation:

the speed of the object right before it hits the ground is 
Answer:
The fish is experiencing a water pressure of 502.8 kPa.
Explanation:
The water pressure the fish is experiencing can be found as follows:
(1)
Where:
g: is the gravity = 9.81 m/s²
h: is the height (depth) = 50.0 m
ρ: is the seawater's density = 1.025 g/cm³
By replacing the above values into equation (1) we have:
Therefore, the fish is experiencing a water pressure of 502.8 kPa.
I hope it helps you!