7. Jamal is rolling along on his 4.0 kg skateboard with a constant speed of 3.0 m/s when he jumps off the back and continues forward with a velocity of 2.0 m/s relative to the ground. This
causes the skateboard to go flying forward with a speed of 15.5 m/s relative to the ground.
What is Jamal's mass?

Apositive rod is placed to the left of sphere a, and the spheres are separated. which best describes the spheres? sphere a is negative and sphere b is positive because protons from sphere a are attracted to the rod and move to sphere b. sphere a is negative and sphere b is positive because electrons from sphere b are attracted to the rod and move to sphere a. sphere a is positive and sphere b is negative because electrons from the rod move to sphere b and protons then move to sphere a. sphere a is positive and sphere b is negative because protons move from sphere b to the rod and also to sphere a.

If element x has 99 protons how many electrons does it have

How many electrons in an atom could have these sets of quantum numbers? =3n=3 electronselectrons =4,ℓ=2n=4,ℓ=2 electronselectrons =6,ℓ=ℓ=−1n=6,ℓ=2,mℓ=−1