Answer:
679.2 m/s
Explanation:
The formula for the time of flight of a projectile is given as,
T = 2usinФ/g ......................... Equation 1
Where T = Time of flight, u = initial velocity, Ф = angle of projectile to the horizontal, g = acceleration due to gravity.
make u the subject of the equation
u = Tg/2sinФ....................... Equation 2
Given: T = 69 s, Ф = 30°
Constant: g = 9.8 m/s²
Substitute into equation 2
u = (69×9.8)/(2×sin30)
u = 679.2 m/s.
Hence the initial speed of the projectile is 679.2 m/s
Acceleration occurs whenever the forces on an object are unbalanced.
It's the group of forces on the object that's either balanced or unbalanced.
There's no such thing as "an unbalanced force".
Are you questioning when does evalution start..?
The material that the cylinder is made from is Butyl Rubber.
<h3>What is Young's modulus?</h3>
Young's modulus, or the modulus of elasticity in tension or compression, is a mechanical property that measures the tensile or compressive strength of a solid material when a force is applied to it.
<h3>Area of the cylinder</h3>
A = πr²
<h3>Young's modulus of the cylinder</h3>
Where;
When 5 kg mass is applied, the extension = 10 cm - 9.61 cm = 0.39 cm = 0.0039 m.
When the mass is 50 kg,
extension = 10 cm - 7.73 cm = 2.27 cm = 0.0227 m
The Young's modulus is between 0.001 GPa to 0.002 GPa
Thus, the material that the cylinder is made from is Butyl Rubber.
Learn more about Young's modulus here: brainly.com/question/6864866