Answer:
A maximum
Explanation:
When displacement is maximum, velocity is Zero and vice versa
When displacement is maximum, acceleration is maximum and when it is zero, acc. Is zero
Answer:
a) 70 N, b) b. Each initially applied a force bigger than static friction to get the box moving and accelerating, then when the desired final speed was achieved they reduced the force to make the net force zero.
Explanation:
a) A constant speed means that magnitude of friction force is equal to the magnitude of the external force. The friction force is directly proportional to the normal force, which is equal to the weight of the box. Therefore, the magnitude of the force is 70 N.
b) Alice used initially a greater force to accelerate the box up to needed speed and later reduced the external force to keep speed constant. The right choice is option b.
Answer: C. Africa
Explanation:
The data given on the graph shows that:
Asia will grow from around 1,300 million to 5,000 million in 2050 which is an increase of:
= 5,000 /1,300 = 3.84 times
Europe will decrease over that period.
Africa will go from around 300 million to 2,000 million which is an increase of:
= 2,000 / 300
= 6.67 times
Mexico
, Central America, Caribbean Islands:
= 900 / 120
= 7.5 times
United States, Canada, and Greenland:
= 400/120
= 3.33
Oceania:
= 50 / 13
= 3.85
From the options give, Africa will see the greatest increase at 6.67 times its population in 1950.
Answer:
C. The final kinetic energy is equal to the initial potential energy.
Explanation:
Based on the Principle of energy conservation:
Sum of the Initial Energy = Sum of the Final Energy
Initial Kinetic Energy + Initial Potential Energy = Final Kinetic Energy + Final Potential Energy..........(1)
Since according to the question:
Initial Kinetic Energy = 0
Final Potential Energy = 0
The equation (1) above reduces to
Initial Potential Energy = Final Kinetic Energy
