Answer:
the path the object follows is called its trajectory so A. trajectory
The only statement on the options that says true about density is:> The density of an object determines whether it will sink or float.
Why?Density is a physical property of an object.
Density is not derived as a unit of measure. It is derived from 2 fundamental units: kg and m.
The Density of an object is not constant.
Density is calculated by dividing the mass by the volume of an object.
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The density of an object is constant.
Density is a derived unit of measure
The density of an object determines whether it will sink or float.
Answer:
1.) Time t = 3.1 seconds
2.) Height h = 46 metres
Explanation:
given that the initial velocity U = 30 m/s
At the top of the trajectory, the final velocity V = 0
Using first equation of motion
V = U - gt
g is negative 9.81m/^2 as the object is going against the gravity.
Substitute all the parameters into the formula
0 = 30 - 9.81t
9.81t = 30
Make t the subject of formula
t = 30/9.81
t = 3.058 seconds
t = 3.1 seconds approximately
Therefore, it will take 3.1 seconds to reach to reach the top of its trajectory.
2.) The height it will go can be calculated by using second equation of motion
h = ut - 1/2gt^2
Substitutes U, g and t into the formula
h = 30(3.1) - 1/2 × 9.8 × 3.1^2
h = 93 - 47.089
h = 45.911 m
It will go 46 metres approximately high.
