Answer:
The resulting velocity of the ball after it hits the racket was of V= 51.6 m/s
Explanation:
m= 55.6 g = 0.0556 kg
t= 2.8 ms = 2.8 * 10⁻³ s
F= 1290 N/ms * t - 330 N/ms² * t²
F= 1024.8 N
F*t= m * V
V= F*t/m
V= 51.6 m/s
Answer:
v = 0.41 m/s
Explanation:
- In this case, the change in the mechanical energy, is equal to the work done by the fricition force on the block.
- At any point, the total mechanical energy is the sum of the kinetic energy plus the elastic potential energy.
- So, we can write the following general equation, taking the initial and final values of the energies:

- Since the block and spring start at rest, the change in the kinetic energy is just the final kinetic energy value, Kf.
- ⇒ Kf = 1/2*m*vf² (2)
- The change in the potential energy, can be written as follows:

where k = force constant = 815 N/m
xf = final displacement of the block = 0.01 m (taking as x=0 the position
for the spring at equilibrium)
x₀ = initial displacement of the block = 0.03 m
- Regarding the work done by the force of friction, it can be written as follows:

where μk = coefficient of kinettic friction, Fn = normal force, and Δx =
horizontal displacement.
- Since the surface is horizontal, and no acceleration is present in the vertical direction, the normal force must be equal and opposite to the force due to gravity, Fg:
- Fn = Fg= m*g (5)
- Replacing (5) in (4), and (3) and (4) in (1), and rearranging, we get:


- Replacing by the values of m, k, g, xf and x₀, in (7) and solving for v, we finally get:

We shall consider two properties:
1. Temperature difference
2. Thermal conductivity of the material
Use a cylindrical rod of a given material (say steel) which is insulated around its circumference.
One end of the rod is dipped in a large reservoir of water at 100 deg.C and the other end is dipped in water (with known volume) at 40 deg. C. The cold water if stored in a cylinder which is insulated on all sides. A thermometer reads the temperature of the cold water as a function of time.
This experiment will show that
(a) heat flows from a region of high temperature to a region of lower temperature.
(b) The thermal energy of a body increases when heat is added to it, and its temperature will rise.
(c) The thermal conductivity of water determines how quickly its temperature will rise. If mercury replaces water in the cold cylinder, its temperature will rise at a different rate because its thermal conductivity is different.
Answer:
The water level in the bath tub is rising at a rate of 0.0111 ft/s
Explanation:
Volume of the bath tub = (Area of base) × (height)
Area of base = 18 ft² (constant)
Height = h (variable)
V = 18h
(dV/dt) = 18 (dh/dt)
If (dV/dt) = 0.2 ft³/s
0.2 = 18 (dh/dt)
(dh/dt) = (0.2/18)
(dh/dt) = 0.0111 ft/s
Hope this Helps!!!