A) car is raised off the table to the top of the track. how much total work is done on the car? b) if the car is released from rest how much potential energy does the car have at the top of the track? how much kinetic energy?

Wtens = (20 N) * (5 m) * cos (0 deg) = +100 Joules

Wgrav = (20 N) * (5 m) * cos (180 deg) = -100 Joules

Wapp= (10 N) * (5 m) *cos (0 degrees) = +50 Joules

Wfrict =(10 N) * (5 m) * cos (180 degrees) = -50 Joules

Wapp = (10 N) * (5 m) * cos (0 deg) = +50 Joules

Wfrict = (10 N) * (5 m) * cos (180 deg) = -50 Joules

Explanation:

Apply the work equation to determine the amount of work done by the applied force in each of the three situations described below.

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.

kepler used the data from tycho blahe (his mentor) to construct the laws of planetary motion.