The answer is average speed
<span>When the question says the ball lands a distance of 235 meters from the release point, we can assume this means the horizontal distance is 235 meters.
Let's calculate the time for the ball to fall 235 meters to the ground.
y = (1/2)gt^2
t^2 = 2y / g
t = sqrt{ 2y / g }
t = sqrt{ (2) (235 m) / (9.81 m/s^2) }
t = 6.9217 s
We can use the time t to find the horizontal speed.
v = d / t
v = 235 m / 6.9217 s
v = 33.95 m/s
Since the horizontal speed is the speed of the plane, the speed of the plane is 33.95 m/s</span>
I’m pretty sure it’s kinetic energy
The figure mentioned on the question is in the attachment.
Answer: a) 
= - 38.35N
b) 
= 30.5 N
c) 
= 27.45 N
d) a = - 13.16 m/s²
Explanation: A block on an inclined plane has 3 forces acting on it:
- Force due to gravity
= m.g; - Normal Force due to the plane;
- Force of Friction = µ.N;
Since the plane is inclined, Normal Force is equal the y-component of the force due to gravity and Force of friction and the x-component of the force due to gravity are opposite forces.
The second attachment ilustrate the forces acting on the block.
Calculating:
A) The magnitude of the x-component of Force due to gravity:
According to the second image:
= P.sinθ
= 5.9.8.sin(36.8)
= - 38.35 N
B) = 
= m.g.cosθ
= 5.9.8.cos(36.8)
= 30.5 N
C) = 0.9.30.5
= 27.45 N
D) For the acceleration, use Newton's Law: 
= m . a
If there is movement, it is only on x-axis, so the net force is:
- = m.a
- 38.35 - 27.45 = 5a
a = - 13.16 m/s²
The value of acceleration shows there is <u>no</u> <u>movement</u> on the x-axis due to the friction.
Answer:
<em>The density of rock = 3.37 g/cm³</em>
Explanation:
Density: Density can be defined as the ratio of the mass of a body to the volume. The S.I unit of density is kg/m³. It can be expressed mathematically as ,
D = M/V............................................... Equation 1
Where D = density of the body, M = mass of the body, V = volume of the body.
From Archimedes' principle, a body will displace a volume of water equal to its volume.
Therefore, Volume of the object = volume of water displaced
<em>Given: M = 300 g, V = volume of water displace = 89.0 cm³.</em>
<em>Substituting these values into equation 1</em>
<em>D = 300/89</em>
<em>D = 3.37 g/cm³</em>
<em>The density of rock = 3.37 g/cm³</em>
