Answer:
48.7 J
Explanation:
For a mass-spring system, there is a continuous conversion of energy between elastic potential energy and kinetic energy.
In particular:
- The elastic potential energy is maximum when the system is at its maximum displacement
- The kinetic energy is maximum when the system passes through the equilibrium position
Therefore, the maximum kinetic energy of the system is given by:
where
m is the mass
v is the speed at equilibrium position
In this problem:
m = 3.6 kg
v = 5.2 m/s
Therefore, the maximum kinetic energy is:
Answer:
KE + PE = KE + PE
Explanation:
In a closed system, the mechanical energy of the system is constant.
Mechanical energy is given by the sum of kinetic energy and potential energy; mathematically:
U = KE + PE
where
KE is the kinetic energy
PE is the potential energy
This means that if we consider two situations, one at the beginning and one at the end, the value of U will not change if the system is closed; this means that the sum KE + PE will remain the same, so we can write:
KE + PE = KE + PE
Answer: length of B =4.00
Explanation:
for the vectors A and B and the angle between them as x.
Magnitude of the sum of A and B is given as = √(A²+B²+2ABcosx
where
Magnitude of A = 3.00
Magnitude of the sum of A and B is 5.00
5.00=√(A²+B²+2ABcos90°
5.00= √3² +b² +0
5²= 3² +b²
25=9+b²
b²= 25-9
b² = 16
b= √16
b= 4
Answer:
B 14.5 m/s to the east
Explanation:
We can solve this problem by using the law of conservation of momentum.
In fact, if the system is isolated, the total momentum of the system must be conserved.
Here the total momentum before the stuntman reaches the skateboard is:
where
M = 72.0 kg is the mass of the stuntman
v = 15.0 m/s is his initial velocity (to the east)
The total momentum after the stuntmen reaches the skateboard is:
where
m = 2.50 kg is the mass of the skateboard
v' is the final velocity of the stuntman and the skateboard
Since momentum must be conserved, we have
And solvign for v',
And since the sign is the same as v, the direction is the same (to the east).
Nothing can travel faster than the speed of light. As such, perceptions of objects and time change as they approach light speed, but the laws of physics remain consistent regardless of speed. Objects will appear shortened and time will appear to slow down around an observer approaching near light speeds, but all quantities still exist as they did before and all causality is preserved, even if observers in different points or traveling at different speeds will report different things.
