Answer:
D
Explanation:
Moji could've chosen hardness tests that were not reliable.
Answer:True
Explanation:
When we rub a glass rod with silk cloth electrons of glass rod are stripped away by the silk cloth making glass rod Positively charged i.e. relatively glass rod has more positive charge than negative charge.
During this Process no charge is created but transfer of the charges makes the rod relatively Positive and silk cloth relatively negative.
Thus net charge is same and no new charge is created.
Answer:
b. cannot be effectively tested
Explanation:
Answer:
0.686 m/s
Explanation:
The principle of conservation says the sum of momenta before collision is equal to the sum of momenta after collision in an isolated system. Here, we assume the system is not acted upon by any external force.
The initial momentum = momentum of 1 st cart + momentum of 2nd cart
= 0.400 × 1.2 + 0.300 × 0 = 0.48 kg m/s
The final momentum = (0.400 + 0.300) × v (since they stick together)
0.700 v = 0.48
v = 0.686 m/s