Answer:

Explanation:
From the exercise we have that

<em><u>To find how far from the edge of the piano does the cat strike the floor, we need to calculate its time first </u></em>

At the end of the motion y=0m

Solving for t
or 
Since the <u>time</u> can't be negative the answer is t=0.73
Knowing that we can calculate how far does the cat strike the floor

No, it will only melt if the temperature is lowered. If you compress it, it will change the shape, but it will not change the state it is in (i.e. solid).
Answer:
A.
Explanation:
momentum depends on weight and speed
From the given problem, a limit on the depression of a building is placed at 20 centimeters. To solve how many floors can be safely added, a quantity of how many cm will a building sink for each floor that is added is needed. Unfortunately, it is not found anywhere in the problem. However, we can provide a formula to solve for the depression. This is as follows:
Building depression < 20 cm
Building depression = (cm depression per floor) * (no. of floors)
Answer:
the number density of the protons in the beam is 3.2 × 10¹³ m⁻³
Explanation:
Given that;
diameter D = 2.0 mm
current I = 1.0 mA
K.E of each proton is 20 MeV
the number density of the protons in the beam = ?
Now, we make use of the relation between current and drift velocity
I = MeAv ⇒ 1 / eAv
The kinetic energy of protons is given by;
K = 
v²
v = √( 2K /
)
lets relate the cross-sectional area A of the beam to its diameter D;
A =
πD²
now, we substitute for v and A
n = I /
πeD² ×√( 2K /
)
n = 4I/π eD² × √(
/ 2K )
so we plug in our values;
n = ((4×1.0 mA)/(π(1.602×10⁻¹⁹C)(2mm)²) × √(1.673×10⁻²⁷kg / 2×( 20 MeV)(1.602×10⁻¹⁹ J/ev )
n = 1.98695 × 10¹⁸ × 1.6157967 × 10⁻⁵
n = 3.2 × 10¹³ m⁻³
Therefore, the number density of the protons in the beam is 3.2 × 10¹³ m⁻³