When a body weighing 0.5 kg was thrown at an angle of 15 degrees, an energy of 100 joules was expended on the horizon.

When a body weighing 0.5 kg was thrown at an angle of 15 degrees, an energy of 100 joules was expended on the horizon. How far from the throwing point horizontally the body will fall.

The x-axis is horizontally from the point of throw, the y-axis is upward vertically

Immediately after the throw, the body had only kinetic energy E = 100 J:

E = mv2 / 2.

Starting speed:

V = root (2E / m);

Vх – horizontal component of speed (constant).

Vх = v * cos a;

Vy – vertical component of speed:

Vy = V * sin a – gt.

At the top point of the trajectory Vy = 0:

0 = V * sin a – gt,

where g is the acceleration due to gravity.

Time to reach the top:

t = (V * sin a) / g.

Answer: 20 m.