Answer:
1)

2)

Explanation:
<u>Projectile Motion</u>
When an object is launched near the Earth's surface forming an angle
with the horizontal plane, it describes a well-known path called a parabola. The only force acting (neglecting the effects of the wind) is the gravity, which acts on the vertical axis.
The heigh of an object can be computed as

Where
is the initial height above the ground level,
is the vertical component of the initial velocity and t is the time
The y-component of the speed is

1) We'll find the vertical component of the initial speed since we have not enough data to compute the magnitude of 
The object will reach the maximum height when
. It allows us to compute the time to reach that point

Solving for 

Thus, the maximum heigh is

We know this value is 8 meters

Solving for 

Replacing the known values


2) We know at t=1.505 sec the ball is above Julie's head, we can compute




Answer
given,


mass of book = 0.305 Kg
so, from the diagram attached below




computing horizontal component




θ = 62.35°
In determining the number of significant figures in a
given number, there are three rules to always remember / follow:
First: All integers except
zero are always significant.
<span>Second: Any zeros located between
non zeroes are always significant.</span>
Third: A zero located
after a non zero in a decimal is always significant whether it is before or
after the decimal
Therefore using this rule,
the number of significant digits in the given numbers are:
(a) 214 = 3
(b) 81.60 = 4
(c) 7.03 = 3
(d) 0.03 = 1
(e) 0.0086 = 2
(f) 3236 = 4
(g) 8700 = 2
The statement that could be made about the energy in this situation would be :
It being transferred from his arms muscles to the ball.
The muscle contraction from his arms created a force that could be used to lift the ball up.<span />
Answer:
E) I = 18.4 N.s
Explanation:
For this exercise let's use momentum momentum
I = Δp =
- p₀
The energy of the stone is only kinetic
K = ½ m v²
The initial energy is Ko and the final is 70% Ko
= 0.70 K₀
energy equation
= 0.7 ½ m v₀²
You can also write
= ½ m vf²
½ m vf² = ½ m (0.7 v₀²)
= v₀ √ 0.7
Now we can calculate and imposed
I = m (-vo √0.7) - m vo
I = m vo (1 +√0.7
I = 0.5000 20.0 (1.8366)
I = 18.4 N.s