Answer:
P = 1333.33 N
Explanation:
The pressure exerted by the boy on the floor can be calculated by the following equation:
where,
P = Pressure exerted by the boy = ?
F = Force Applied = Weight of Boy = 40 kg = 40 N (since 1 kg = 1N)
A = Area of application of force = 2(Area of one show) = 2(6 cm x 25 cm)
A = 2(0.06 m x 0.25 m) = 0.03 m²
Therefore,
<u>P = 1333.33 N</u>
Answer:
Explanation:
Expression for velocity of wave produced in a hanging wire can be given as follows
Velocity v =
where T is tension in wire and m is mass of wire per unit length.
In the given case
T = Mg + mg
= Mg
neglecting weight of rope
mass of the rope per unit length
= m / L
Velocity of wave
=
=
Answer:
The rock must leave the cliff at a velocity of 28.2 m/s
Explanation:
The position vector of the rock at a time t can be calculated using the following equation:
r = (x0 + v0x · t, y0 + 1/2 · g · t²)
Where:
r = position vector at time t.
x0 = initial horizontal position.
v0x = initial horizontal velocity.
t = time.
g = acceleration due to gravity (-9.81 m/s² considering the upward direction as positive).
Please, see the attached figure for a graphical description of the problem. Notice that the origin of the frame of reference is located at the edge of the cliff so that x0 and y0 = 0.
When the rock reaches the ground, the position vector will be (see r1 in the figure):
r1 = (90 m, -50 m)
Then, using the equation of the vector position written above:
90 m = x0 + v0x · t
-50 m = y0 + 1/2 · g · t²
Since x0 and y0 = 0:
90 m = v0x · t
-50 m = 1/2 · g · t²
Let´s use the equation of the y-component of the vector r1 to find the time it takes the rock to reach the ground and with that time we can calculate v0x:
-50 m = 1/2 · g · t²
-50 m = -1/2 · 9.81 m/s² · t²
-50 m / -1/2 · 9.81 m/s² = t²
t = 3.19 s
Now, using the equation of the x-component of r1:
90 m = v0x · t
90 m = v0x · 3.19 s
v0x = 90 m / 3.19 s
v0x = 28.2 m/s
