A780g, 50-cm-long metal rod is free to rotate about a frictionless axle at one end. while at rest, the rod is given a short but sharp 1000n hammer blow at the center of the rod, aimed in a direction that causes the rod to rotate on the axle. the blow lasts a mere 2.5ms.

what is the rod's angular velocity immediately after the blow? the book gives the answer 8.0rad/s

9.6 rad/s

Explanation:

= length of the metal rod = 50 cm = 0.50 m

= Mass of the long metal rod = 780 g = 0.780 kg

Moment of inertia of the rod about one end is given as

= force applied by the hammer blow = 1000 N

Torque produced due to the hammer blow is given as

= time of blow = 2.5 ms = 0.0025 s

= Angular velocity after the blow

Using Impulse-change in angular momentum, we have

the answer is neither ball has a charge.

because if they were both positively charged, they will repel each other.

if they were positively and negatively charged, they will seek.

the higher the current the higher the mag field around it the higher the influence on the compass