Answer: v = 
Explanation: q = magnitude of electronic charge = 
mass of an electronic charge =
V= potential difference = 4V
v = velocity of electron
by using the work- energy theorem which states that the kinetic energy of the the electron must equal the work done use in accelerating the electron.
kinetic energy =
, potential energy = qV
hence, 

1.Record her observation with the time it was hot.
2. Gather info about the pavement and its surroundings. Find out what it's made of and what its temp. is at different times of the day.
3. Come up with a hypothesis about why it is hot.
4. Design an experiment to test the hypothesis. If she thinks the Sun is responsible (which she should b smart enough to know), keep it covered during the day time and check it's temp.
5. Come up with a conclusion. If her hypothesis is not supported, design a new experiment or gather more info.
Photovoltaic cells are the most efficient means of converting solar energy to electricity. Option b is correct.
<h3>What is a cell?</h3>
A cell is a voltage and current-producing device that consists of a single anode and cathode separated by an electrolyte.
One or more cells can make up a battery. One cell, for example, is one AA battery.
Light intensity on a solar cell is often measured in "suns," with one sun roughly equivalent to 1 kW/m².
Concentrated sunlight improves the ratio of current generated while the device is lighted vs when it is dark, hence enhancing output voltage and efficiency.
Photovoltaic cells are the most efficient means of converting solar energy to electricity.
Hence, option b is correct.
To learn more about the cell refer to:
brainly.com/question/3142913
#SPJ1
Answer:
34.3 m/s
Explanation:
Newton's Second Law states that the resultant of the forces acting on the car is equal to the product between the mass of the car, m, and the centripetal acceleration
(because the car is moving of circular motion). So at the top of the hill the equation of the forces is:

where
(mg) is the weight of the car (downward), with m being the car's mass and g=9.8 m/s^2 is the acceleration due to gravity
R is the normal reaction exerted by the road on the car (upward, so with negative sign)
v is the speed of the car
r = 0.120 km = 120 m is the radius of the curve
The problem is asking for the speed that the car would have when it tires just barely lose contact with the road: this means requiring that the normal reaction is zero, R=0. Substituting into the equation and solving for v, we find:
