Answer:
a)
reaction time = 0.70 s
distance travelled in reaction time = v*t
= 20 m/s * 0.70 s
= 14 m
So, when brake is applied, distance remaining= 110 m - 14 m = 96 m
Answer: 96 m
b)
vf = 0 m/s
d = 96 m
vi = 20 m/s
use:
vf^2 = vi^2 + 2*a*d
0 = 20^2 + 2*a*96
-400 = 2*a*96
a = -2.08 m/s^2
Answer: -2.08 m/s^2
c)
use:
vf = vi + a*t
0 = 20 - 2.08*t
t = 9.6 s
Answer: 9.6 s
Explanation:
Answer:
1. The frequency of the incident light must be equal to or greater than the threshold frequency of the photons before emission could take place.
2. The intensity of the incident light is proportional to the amount of photons released. The higher the intensity of light, the greater the amount of photons ejected.
Explanation:
1. Photoelectric effect is the process by which light with sufficient frequency falls on the surface of a material, e.g metal, to emit electrons. The incident light must have a minimum value of required frequency for the electrons to be ejected. This energy is termed work function which is a function of frequency.
So for emission to take place, the frequency of the incident light must be equal to or greater than the threshold frequency of the photons.
2. The intensity of light is a measure of the amount of light per unit area. When the intensity of incident light increases, the probability that photons would be released increases. The intensity of the incident light is proportional to the amount of photons released.
The answer is A. Cones, as rods are not sensitive to color. :)
Answer:
Janet jumps off a high diving platform with a horizontal velocity of 2.89 m per s and lands in the water 1.5 s later. How high is the platform?
Platform is 11.025 meters high .
Explanation:
we have Vx = 2.89 m/s
time taken = 1.5 seconds
height of the platform = ?
so,
As Janet is jumping from a high diving platform from a certain unknown height their must be involvement of gravity in action.
we can use,
h = Vi*t+(1/2)*g*t^2
where ,
h = height
Vi = initial horizontal velocity that will be zero
t = time in seconds
g = gravity due to acceleration
now put the values
h = 0+(1/2)*(9.8)*(1.5)^2
h = 11.025-m
Answer: B) He has too many independent variables.
Explanation: Nothing in the experiment is a constant or being measured.
