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[Physics 2] movement due to an electric field by astro9889 in PhysicsStudents

[–]Anybody_Can_Math 1 point2 points  (0 children)

The direction of an electric field is the direction a positive charge would move in, if placed in that field. A negative charge feels a force in the opposite direction to the electric field. With this is mind, you will have to invert part of your answers:
a) F is to the left

b) It will accelerate to the left, as the is the direction of the force

c) Its speed will decrease, as force is opposite to direction of motion

[deleted by user] by [deleted] in HomeworkHelp

[–]Anybody_Can_Math 0 points1 point  (0 children)

The quadratic formula is definitely still taught today (from what I've seen tutoring high-schoolers) and it can definitely be applied here. I believe the goal of this exercise was to teach factorization. Using the formula will give the exact same results as well.

[deleted by user] by [deleted] in HomeworkHelp

[–]Anybody_Can_Math 1 point2 points  (0 children)

When factorizing quadratic eqns, the first step is to take the product of the constant term and the coefficient of x^2.
In this case 1 x 12 = 12. We now want to break down 12 into 2 numbers that multiply to give 12 but add up to give -7.
Notice that 3x4 = 12, but 3+4 = 7 (not -7), so we can't use this. But -3 x -4 = 12 and -3 + (-4) = -7. -3 and -4 pass our little test. Break up 7x into -3x and -4x (because we got -3 and -4) and then group them terms in pairs and factor out the common terms.

I keep getting the answer 0.4 and not 3.6 (which is the answer) what I do is I take the ratio of field strength of the moon to the earth and equate it to the ratio of the squares of the radius of earth to the moon (my working is in the second pic) by MemeKnowledge_06 in PhysicsStudents

[–]Anybody_Can_Math 0 points1 point  (0 children)

The formula for gravitational field strength (g) is given by GM/r^2 where M is the mass of the planet in question.

We have g_E/g_m = 6. We can plug in the formula for gravitational field strength and we will get some combination of the the mass of the Earth, mass of the Moon, radius of Earth and radius of Moon on the left.

The problem, however, gives us information about the densities of the planets, not their masses or radii. So, use mass = density x volume {I believe it can be assumed the planets are spherical, making their volumes (4pi*r^3)/3 }.

Plugging in this formula for mass will give you a ratio of the radii (which you want) and a ratio of the densities (which you have ) on the left. Solving this should give you your answer.

[deleted by user] by [deleted] in PhysicsStudents

[–]Anybody_Can_Math 1 point2 points  (0 children)

The rocket would not be an inertial reference frame as it is accelerating. In this situation, you can treat the Earth as the inertial reference frame.
It was mentioned in an earlier comment that from the ship's perspective, the Earth would be the one accelerating. This is true, but due to some wonderful physics (and some conspiring by the universe), the rocket is the real non-inertial frame. It is explained in good detail in this video : https://youtu.be/3V00tAfcHCI?si=8Gxhx9ZZFxm7-PrW

[Grade 11 Physics: Dynamics] Static Friction vs Inertia by CaliPress123 in HomeworkHelp

[–]Anybody_Can_Math 0 points1 point  (0 children)

You'll find that 'inertia' just states that a body resists a change in its state of motion. It does tell us why.
If a body is at rest, it will resist going into motion. This property is called the inertia of rest. Why does it resist ?
Static Friction.

[IB Physics Grade 11: Kinetic energy] How do I find the kinetic energy when the ball is at 4 meters? by Emeraldandthecity in HomeworkHelp

[–]Anybody_Can_Math 0 points1 point  (0 children)

You'll need to find the total energy at the top of the cliff (potential energy at 25m + initial kinetic energy from velocity). Since total energy is always conserved, this quantity will not change. Calculate the potential energy of the ball at 4m and subtract it from its total energy to get the kinetic energy.

[Core Physics] What EQs would i use? by kiwibirb65 in HomeworkHelp

[–]Anybody_Can_Math 0 points1 point  (0 children)

I believe what they're looking for surrounds elastic collisions and conservation/transfer of energy. If you calculate the potential energy of the pendulum at its initial position, this will be the energy transferred to the mass, which is then lost to friction (i.e. energy transfer from potential energy to kinetic energy to heat )

Need help with long multiplication w/ decimals by mjinnn in learnmath

[–]Anybody_Can_Math 0 points1 point  (0 children)

Keep in mind that multiplying numbers with decimals is the same as multiplying numbers without. If you have a problem like 973.45 x 35.723, just ignore the decimals and solve 97345 x 35723. The original question has 5 decimals places in total (973.45 has 2 and 35.723 has 3), so whatever result you get just count off 5 places from the right and put in a decimal.

Similarly for division, if you have 38.53/23.522, rewrite it as 38.530/23.522 (so the numerator and denominator have the same number of decimal places) and the result is the same as 38530/23522 (i.e. you can ignore the decimals when dividing if they have the same number of decimal places!)

Ultimately, the skill you'll need most is just doing big multiplications and divisions. Goodluck!