Robyn has been working out five days a week for the past six months. She is now planning to take a month-long break from the gym
1 answer:
You might be interested in
Answer:
The speed decreases 75%.
Explanation:
- Since no friction present, assuming no external forces acting during the three collisions, total momentum must be conserved.
- For the first collission, only mass 1 is moving before it, so we can write the following equation:
- Since both masses are identical, and they stick together after the collision, we can express the final momentum as follows:
- From (1) and (2) we get:
- v₁ = v₀/2 (3)
- Since the masses are moving on a frictionless 1D track, the speed of the set of mass 1 and 2 combined together before colliding with mass 3 is just v₁, so the initial momentum prior the second collision (p₁) can be expressed as follows:
- Since after the collision the three masses stick together, we can express this final momentum (p₂) as follows:
- From (4) and (5) we get:
- v₂ = v₀/3 (6)
- Since the masses are moving on a frictionless 1D track, the speed of the set of mass 1, 2 and 3 combined together before colliding with mass 4 is just v₂, so the initial momentum prior the third collision (p₂) can be expressed as follows:
- Since after the collision the four masses stick together, we can express this final momentum (p₃) as follows:
- From (7) and (8) we get:
- v₃ = v₀/4
- This means that after the last collision, the speed will have been reduced to a 25% of the initial value, so it will have been reduced in a 75% regarding the initial value of v₀.
Answer:
Explanation:
To solve the problem, the concepts related to the magnetic field and the current produced in a lightning bolt are necessary.
The current is defined by the load due to time, that is to say
Where,
So the current can be expressed as:
Once the current is found it is now possible to find the magnetic field, as this is given by the equation,
Where,
Permeability Constant
I= Current
r= radius
Replacing the values we have
Relative to the positive horizontal axis, rope 1 makes an angle of 90 + 20 = 110 degrees, while rope 2 makes an angle of 90 - 30 = 60 degrees.
By Newton's second law,
- the net horizontal force acting on the beam is
where are the magnitudes of the tensions in ropes 1 and 2, respectively;
- the net vertical force acting on the beam is
where and
.
Eliminating , we have
Solve for .