Answer:
l = 4.33 m
Explanation:
given,
mass of solid sphere = 390 gram = 0.39 kg
radius = R = 19 cm = 0.19 m
rolling with constant speed = 4 m/s
angle with horizontal = 15°
acceleration due to gravity = 10 m/s²
using energy conservation

I for sphere
v = r ω




h = 1.12 m


l = 4.33 m
the sphere will travel 4.33 m on the ramp.
Answer:
Potential energy plus kinetic energy equals mechanical energy because mechanical energy is basically just all of an object's energy, it's just two kinds of energy. The potential is stored inside and kinetic is being used. Both of those together is the total amount of the objects energy, which is the mechanical energy.
Explanation:
Relative speed of Tina with respect to David is given by



now the acceleration of Tina with respect to David



now the relative displacement would be zero when Tina cross David
so now we have



now the speed of Tina at this moment is given as



<em>so the speed will be 52 m/s</em>
Copper is the higher concentrated metal in this case.