A football player kicks a ball horizontally off a hill with an initial velocity of 42.0 m/s. It travels a horizontal distance of 59.2m. How y’all was the hill he kicked the ball off of?

9.74 m

Explanation:

Given the following :

Initial Velocity(u) = 42m/s

Horizontal distance (d) = 59.2m

Using the motion equation:

H = ut + 0.5×g×t^2

Where H = height, g = acceleration due to gravity (9.8m/s^2), t = time, u= Initial Velocity

Time(t) = horizontal distance / velocity

t = 59.2 / 42 = 1.41seconds

Therefore,

H = (0 × 1.41) + 0.5(9.8)×(1.41)^2

H = 0 + 9.74169

H = 9.74m

at positions a, g kinetic energy is maximum.

at position d, potential energy is maximum.

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.