The kinetic energy is given by:
We know the mass and the maximum speed, plugging their values in the expression above we have:
Therefore, the answer is d.
28. Ken and Musa shared a cake such that Ken got twice the size
1 answer:
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Answer:
Electromagnetic force
Explanation:
There are four fundamental forces in nature:
- Gravity: it is the force that is exerted between any objects with mass. It is the weakest of all forces, so it is only relevant at planetary scales. It is always attractive, and it has an infinite range.
- Electromagnetic force: it is the force exerted between charged objects and between magnets (it is responsible for electric fields and magnetic fields). It is the 2nd strongest force, and it is the force that holds atoms in a molecule together. It can be attractive or repulsive, and it has an infinite range.
- Strong nuclear force: it is the strongest of all forces. It is responsible for holding the nucleons together inside the nucleus, and it is attractive. It has a very limited range (), so it is relevant only at very small scales
- Weak nuclear force: it is the force responsible for radioactive decays and neutrino interactions. It also has a very short range (
Looking at all these definitions, we see that the term that defines the force that acts between charged particles is the electromagnetic force.
Answer:
a) p₂ = 1.88 kg*m/s
θ = 273.4 º
b) Kf = 37% of Ko
Explanation:
a)
- Assuming no external forces acting during the collision, total momentum must be conserved.
- Since momentum is a vector, their components (projected along two axes perpendicular each other, x- and y- in this case) must be conserved too.
- The initial momenta of both particles are directed one along the x-axis, and the other one along the y-axis.
- So for the particle moving along the positive x-axis, we can write the following equations for its initial momentum:
- We can do the same for the particle moving along the positive y-axis:
- Now, we know the value of magnitude of the final momentum p1, and the angle that makes with the positive x-axis.
- Applying the definition of cosine and sine of an angle, we can find the x- and y- components of the final momentum of the first particle, as follows:
- Now, the total initial momentum, along these directions, must be equal to the total final momentum.
- We can write the equation for the x- axis as follows:
- We know from (3) that p₀₂ₓ = 0, and we have the values of p₀1ₓ from (1) and pf₁ₓ from (5) so we can solve (7) for pf₂ₓ, as follows:
- Now, we can repeat exactly the same process for the y- axis, as follows:
- We know from (2) that p₀1y = 0, and we have the values of p₀₂y from (4) and pf₁y from (6) so we can solve (9) for pf₂y, as follows:
- Since we have the x- and y- components of the final momentum of the second particle, we can find its magnitude applying the Pythagorean Theorem, as follows:
- We can find the angle that this vector makes with the positive x- axis, applying the definition of tangent of an angle, as follows:
- The angle that we are looking for is just the arc tg of (12) which measured in a counter-clockwise direction from the positive x- axis, is just 273.4º.
b)
- Assuming that both masses are equal each other, we find that the momenta are proportional to the speeds, so we find that the relationship from the final kinetic energy and the initial one can be expressed as follows:
- So, the final kinetic energy has lost a 37% of the initial one.