Hi,
Recall the formula V=d/t, where V stands for velocity or speed, d stands for distance and t stands for time. By substituting your values you get: V=50.0km/2.5h, which equals to 20km/h.
Answer:
The given figure shows two men M and N facing two flat and hard walls, wall 1 and wall 2. Man N fires a gun. Man M hears two echoes, one from wall 1 and second from wall 2. The speed of sound in
air is given to be 325 m/s. After the firing of the gun by the man N, the man M will hear the first echo in how many seconds?
Answer:
d= 100m
Explanation:
Cheetah kinematic
The cheetah moves with uniformly accelerated movement, and the formulas that describe this movement are:
d= v₀*t + (1/2)*a*t² Formula (1)
vf²=v₀²+2*a*d Formula (2)
vf=v₀+a*t Formula (3)
Where:
d:distance in meters (m)
v₀: initial speed in m/s
vf: final speed in m/s
a: acceleration in m/s²
t: time in seconds (s)
Known Data
v₀ =0
a = 4.5 m/s²
vf= 30 m/s.
Problem development
We apply the formula (2) that has known data to calculate the distance :
vf²=v₀²+2*a*d
(30)²= 0 + 2* 4.5* d
d= 100m
Answer: Because between the Earth and Sun there is vacuum
There are three ways in which heat is transmitted:
1. By Conduction, when the transmission is by the direct contact.
2. By Convection, heat transfer in fluids (like water or the air, for example).
3. By<u> Radiation</u>, by the electromagnetic waves (<u>they can travel through any medium and in vacumm</u>)
.
So, the space between the Earth and the Sun is vacuum, this means the energy cannot be transmitted by convection, nor conduction. It must be transmitted by electromagnetic waves that are able to travel with or without a medium, and this is called <u>radiation</u>.
Answer:
a. A dissipative interaction permits a two-way conversion between kinetic and potential energies.
FALSE
in dissipative type of forces energy is not conserved so it is not possible
b. A nondissipative interaction permits a two-way conversion between kinetic and potential energies.
TRUE
in non dissipative type of force there is no energy loss so we can use energy conservation
c. A potential energy function can be specified for a dissipative interaction.
FALSE
Here potential energy is not defined for dissipative type of forces
d. A potential energy function can be specified for a nondissipative interaction.
TRUE
negative gradient of potential energy is equal to non dissipative type of forces