If you weighed 130 pounds on earth, you would weigh ____

A pilot drops a package from a plane flying horizontally at a constant speed. Neglecting air resistance, when the package hits t

RUDIKE [14]

Complete Question:

A pilot drops a package from a plane flying horizontally at a constant speed. Neglecting air resistance, when the package hits the ground the horizontal location of the plane will

A. be behind the package.

B. be over the package.

C. be in front of the package.

D. depend on the speed of the plane when the package was released.

Answer:

B.

Explanation:

As no other horizontal forces are present, due to the horizontal movement and the vertical one are independent each other (as they are perpendicular), the plane and the package continue moving horizontally at the same speed, so when the package hits the ground (due to the action of gravity in the vertical direction only) the plane will be exactly over the package.

7 0

3 years ago

I just don't know how to do the question (a) and (b)

ozzi

Using the equation

$F=ma$

we can observe that you have to apply a non-zero net force to an object in order to make it accelerate. In fact, if the net force is zero you have

$0=ma \iff a=0$

Since we're assuming $n\neq 0$

Now, if the 12N force is applied, the object moves with a constant speed. A constant speed means no acceleration, since by definition the acceleration is a change in speed.

If this sounds counterintuitive to you (why I'm applying a force but I have to acceleration?) think of when we drive a car: even if you want to keep your speed constant, you still have to use the gas pedal, just enough so that the push of the motor balances exactly the road/wheels friction. If you give less gas, the friction becomes stronger, and the car slows down. If you give more gas, the motor push becomes stronger, and the car accelerates.

Back to your exercise: constant speed means to acceleration, so the net force must be zero. This implies that the friction force is exactly 12N.

If the force is increased to 18N, there will be a net force of 6N pushing the object, causing it to accelerate. Using again the same equation of before, and plugging the 3kg mass in the equation, we have

$F=ma \iff 6=3a \iff a=2$

So, the object moves with constant acceleration and initial speed of 10m/s for 0.2 seconds. It's final speed will be

$v = v_0+at = 10+2\cdot 0.2 = 10.4$

5 0

4 years ago

A spring of force constant 285.0 N/m and unstretched length 0.230 m is stretched by two forces, pulling in opposite directions a

Kaylis [27]

Answer: W = 0.3853 J, e = 0.052 m

Explanation: Given that,

K =285.0N/M , L = 0.230m , F = 15N , e = ?

F = Ke

15 = 285 × e

e = 15÷ 285

e =0.052 m

e + L = 0.052 + 0.230

= 0.282m ( spring new length )

Work needed to stretch the spring

W = 1/2ke2

W = 1/2 × 285 x 0.052 × 0.052

W = 0.3853 J

8 0

3 years ago

Consider the following four objects: a hoop, a solid sphere, a flat disk, a hollow sphere. Each of the objects has mass M and ra

Svetlanka [38]

Answer:

Hoop.

Explanation:

The angular acceleration performed at a given torque:

$\alpha = \frac{\tau}{I}$

The moments of inertia of each element are described below:

Hoop

$I = M\cdot R^{2}$

Solid sphere

$I = \frac{2}{5}\cdot M \cdot R^{2}$

Flat disk

$I = \frac{1}{2}\cdot M \cdot R^{2}$

Hollow sphere

$I = \frac{2}{3}\cdot M \cdot R^{2}$

The greater the moment of inertia, the greater the torque to obtain the same angular acceleration. Therefore, the hoop requires the largest torque to receive the same angular acceleration.

8 0

4 years ago

A sound wave generated by a musical note has the characteristics presented

Anuta_ua [19.1K]

Answer:

Explanation:subtract all of those by the all of the other numbers and that’s the answer i think that’s the way I learned it

6 0

3 years ago

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If you weighed 130 pounds on earth, you would weigh _____pounds on the moon