Answer:
The frequency must be: 
Explanation:
If the work function of the metal (
) is 3 eV, then we can use the formula for the kinetic energy of an ejected electron:
considering for the minimum KE = 0, and using the Plank constant h in eV s as: 4.14 * 10 ^(-15) eV s, to solve for the frequency:
Answer:
work = 0
Explanation:
Let's remember that work is defined as the product of a force by a distance. Distance is the physical path displaced by the body under the action of that force.
W = F * d
where:
W = work [J]
F = force [N]
d = distance [m]
In this case, the toy is held at a height, there is no displacement from one point to another. So there is no work and this is equal to zero.
W = (2*9.81) * 0 = 0 [Joules]
When developing a question for a scientific inquiry, the question will ideally D. all of these.
When it comes to a scientific inquiry, it is important that the question identify variables, be measurable, and not just simply ask why. There have to be a couple of variables, you have to be able to measure the results, and to prove them, supported by evidence.
Answer:
a) The initial momentum of the ball is 22.5 kg·m/s
b) The magnitude of the momentum imparted by the ball is 30 kg·m/s
Explanation:
The question is based on change in momentum
The mass of the ball, m = 0.75 kg
The velocity with which the ball is thrown against the wall, u = 30 m/s
The time duration it takes while the ball is in contact with the wall, Δt = 0.05 sec
The velocity of the ball as it bounce back, v = -10 m/s (The ball moves in the opposite direction)
a) The initial momentum of the ball, 
= m × u = 0.75 kg × 30 m/s = 22.5 kg·m/s
b) The final momentum of the ball, 
= m × v = 0.75 kg × (-10 m/s) = -7.5 kg·m/s
The momentum imparted by the ball, ΔP = The final momentum - The initial momentum
∴ ΔP = - = -7.5 kg·m/s - 22.5 kg·m/s = -30 kg·m/s
The magnitude of the momentum imparted by the ball, 
= 30 kg·m/s
Answer:
I agree with Raymond because total energy is conserved
Explanation:
The law of conservation of energy states that energy is neither created nor destroyed, but is transformed from one form to another. As the skateboarder goes up and down the ramp, there is the interconversion of energy between kinetic and potential energy, assuming energy is not lost to heat or other forms of energy.
Kinetic energy is energy in motion, and potential energy is energy at rest. As the skateboarder descends the ramp, the motion increases and the potential energy is converted to kinetic energy, and maximum kinetic energy is attained at the lowest point on the ramp because that is where speed is greatest. However, as the skateboarder ascends the ramp, the kinetic energy decreases progressively and is being converted to potential energy, which is greatest at the top of the ramp, where the skateboarder is momentarily at rest, and speed is zero. Hence at each point on the ramp, total energy is the same.
