Answer:
a) 
b) 
Explanation:
Given the information from the exercise we can calculate the work done by the elevator using the following formula:
a) Considering you and your belongings as a system we know that the elevator is applying a Normal reaction force of:
Since the force applied and the displacement is in the same direction, the work done by the elevator is positive
b) The reaction force applied by the elevator is the same as the weight of the person
Since the force applied and the displacement is in opposite direction, the work done by the elevator is negative
B) the current will decrease
Answer:
A. Two protons and two neutrons.
Explanation:
Alpha particles are positively charged specie identical to the nucleus of Helium atom.
Position displacement velocity acceleration are vectors and the rest are scalars
Answer:a) 34.5 N; b) 24.5 N; c) 10 N; d) 1J
Explanation: In order to solve this problem we have to used the second Newton law given by:
∑F= m*a
F-f=m*a where f is the friction force (uk*Normal), from this we have
F= m*a+f=5 Kg*2 m/s^2+0.5*5Kg*9.8 m/s^2= 34.5 N
then f=uk*N=0.5*5Kg*9.8 m/s^2= 24.5N
the net Force = (34.5-24.5)N= 10 N
Finally the work done by the net force is equal to kinetic energy change so
W=∫Force net*dr= 10 N* 0.1 m= 1J
