The force of earth's gravitational field is always directed downwards (towards the center of the earth. When the ball is thrown up, it is going against the earth's gravitational field and so, the earth's gravitational force pulls it back down, accelerating it downwards.
Answer:
The photoelectric effect occurs only for frequencies above the cutoff frequency, regardless of the intensity.
Explanation:
The photoelectric effect occurs when light is shined on metals such as zinc beyond a certain frequency (the threshold frequency), which causes electrons to escape from the zinc. The electrons which are fleeing are called photo electrons.
Therefore photo electric effect is
The photoelectric effect occurs only for frequencies above the cutoff frequency, regardless of the intensity.
Answer:
The answer is D, I just took the test
Explanation:
a) 10 m/s
b) 25 m
Explanation:
a)
The body is moving with a constant acceleration, therefore we can solve the problem by using the following suvat equation:

where
u is the initial velocity
v is the final velocity
a is the acceleration
t is the time
For the body in this problem:
u = 0 (the body starts from rest)
is the acceleration
t = 5 s is the time
So, the final velocity is

b)
In this second part, we want to calculate the distance travelled by the body.
We can do it by using another suvat equation:

where
u is the initial velocity
v is the final velocity
a is the acceleration
s is the distance travelled
Here we have
u = 0 (the body starts from rest)
is the acceleration
v = 10 m/s is the final velocity
Solving for s,

Answer:c
Explanation:because when u push the oar back u go forward