Answer:
Suck up the iron using the electromagnet.
Explanation:
Iron is magnetic and copper is not. So copper will be
unaffected by the magnet. After extracting the iron,
open the switch. The electromagnet will lose its
magnetism and the iron fillings will fall off..
Answer:
Force is 432.94 N along the rebound direction of ball.
Explanation:
Force is rate of change of momentum.

Final momentum = 0.38 x -1.70 = -0.646 kgm/s
Initial momentum = 0.38 x 2.20 = 0.836 kgm/s
Change in momentum = -0.646 - 0.836 = -1.472 kgm/s
Time = 3.40 x 10⁻³ s

Force is 432.94 N along the rebound direction of ball.
Answer:
0.125 cm
Explanation:
1/f = 1/d¡ + 1/d。
Find the focal point
(13.0^-1 + 20.8^-1) = 0.125 m
Focal point = 0.125 m