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3 years ago

11

if a rock has a speed of 12 m/s as it hits the ground, from what height did it fall assuming the speed was zero.its mass is 50 k

g

2 answers:

Stells [14]3 years ago

8 0

Answer:

7.3 m

Explanation:

jekas [21]3 years ago

5 0

Answer:

a=9.8 ms−2 12^2=0^2+2×9.8×H

H=7.35m

Explanation:

To find the height the following formula should be used: v2=u2+2aH

Assuming this occurs on earth,

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Problem #2: An apple is thrown upward with an initial velocity of +24.0 m/s. a. Sketch the apple's trip and label what you know.

bogdanovich [222]

Answer:

The answer is below

Explanation:

a) The initial velocity (u) = 24 m/s

We can solve this problem using the formula:

v² = u² - 2gh

where v = final velocity, g= acceleration due to gravity = 9.8 m/s², h = height.

At maximum height, the final velocity = 0 m/s

v² = u² - 2gh

0² = 24² - 2(9.8)h

2(9.8)h = 24²

2(9.8)h = 576

19.6h = 576

h = 29.4 m

b) The time taken to reach the maximum height is given as:

v = u - gt

0 = 24 - 9.8t

9.8t = 24

t = 2.45 s

The total time needed for the apple to return to its original position = 2t = 2 * 2.45 = 4.9 s

4 0

3 years ago

Which of the following statements is/are true? Check all that apply. A nonconservative force permits a two-way conversion betwee

saul85 [17]

Answer:

A conservative force permits a two-way conversion between kinetic and potential energies.

The work done by a nonconservative force depends on the path taken.

A potential energy function can be specified for a conservative force.

Explanation:

A conservative force is defined as a force whose work done does not depend on the path taken, but only on the initial and final position of motion.

This means that for a conservative force, it is possible to defined a potential energy function U which depends only on the position of the object. An example of conservative force is gravity: the gravitational potential energy of an object, in fact, depends only on its position in the field, not on the path taken.

This behaviour also implies that when an object moves from A to B and then back from B to A, the potential energy gained (or lost) moving from A to B is lost (or re-gained) when moving from B to A. This means that the total mechanical energy (sum of kinetic energy and potential energy) of the object is conserved, and therefore there is a constant conversion between potential and kinetic energy during the motion.

A non-conservative force instead does not show this properties, as the work done by it depends on the path taken, and therefore it is not possible to define a potential energy function. An example of non-conservative force is friction.

According to what we wrote above, therefore, the only correct statements are:

A conservative force permits a two-way conversion between kinetic and potential energies.

The work done by a nonconservative force depends on the path taken.

A potential energy function can be specified for a conservative force.

3 0

3 years ago

Find the direction and magnitude of Ftot, the total force exerted on her by the others, given that the magnitudes F1 and F2 are

Mars2501 [29]

Answer:

θ = 36°

Explanation:

given,

F₁ = 22.8 N

F₂ = 16.6 N

magnitude of force = ?

direction of force = ?

$F = \sqrt{F_1^2 + F_2^2}$

$F = \sqrt{22.8^2 + 16.6^2}$

$F = \sqrt{795.4}$

F = 28.20 N

direction

$\theta = tan^{-1}(\dfrac{F_2}{F_1})$

$\theta = tan^{-1}(\dfrac{16.6}{22.8})$

$\theta = tan^{-1}(0.728)$

θ = 36°

5 0

3 years ago

An electric bulb is marked 40volts ,230w another bulb is marked 40w,110v

Andrej [43]

Answer:

a. The ratio of their resistance is 2783:64

b. The ratio of their energy is 4:23

c. The charge on the first bulb is 5.75 C

The charge on the second bulb is $0.\overline {36}$ C

Explanation:

The voltage on one of the electric bulbs, V₁ = 40 volts

The power rating of the bulb, P₁ = 230 w

The voltage on the other electric bulbs, V₂ = 110 volts

The power rating of the bulb, P₂ = 40 w

a. The power is given by the formula, P = I·V = V²/R

Therefore, R = V²/P

For the first bulb, the resistance, R₁ = 40²/230 ≈ 6.96

The resistance of the second bulb, R₂ = 110²/40

The ratio of their resistance, R₂/R₁ = (110²/40)/(40²/230) = 2783/64

∴ The ratio of their resistance, R₂:R₁ = 2783:64

b. The energy of a bulb, E = t × P

Where;

t = The time in which the bulb is powered on

∴ The energy of the first bulb, E₁ = 230 w × t

The energy of the second bulb, E₂ = 40 w × t

The ratio of their energy, E₂/E₁ = (40 w × t)/(230 w × t) = 4/23

∴ The ratio of their energy, E₂:E₁ = 4:23

c. The charge on a bulb, 'Q', is given by the formula, Q = I × t

Where;

I = The current flowing through the bulb

From P = I·V, we get;

I = P/V

For the first bulb, the current, I = 230 w/40 V = 5.75 amperes

The charge on the first bulb per second (t = 1) is therefore;

Q₁ = 5.75 A × 1 s = 5.75 C

The charge on the first bulb, Q₁ = 5.75 C

Similarly, the charge on the second bulb, Q₂ = (40 W/110 V) × 1 s = $0.\overline {36}$ C

The charge on the second bulb, Q₂ = $0.\overline {36}$ C.

d. The question has left out parts

4 0

2 years ago

A 2200-kg railway freight car coasts at 4.1 m/s underneath a grain terminal, which dumps grain directly down into the freight ca

777dan777 [17]

Answer:

The answer is " $2.41 \times 10^3$ "

Explanation:

Given:

$m_i = 2000 \ kg \\\\v_i= 4.1 \ \frac{m}{s} \\\\v_f = 3.4 \ \frac{m}{s} \\$

Using formula:

$\to m_iv_i = m_fv_f \\\\\to m_f= \frac{m_iv_i}{v_f}$

$p_i, p_f$ = system initial and final linear momentum.

$V_i, v_f$ = system original and final linear pace.

$m_i$ = original weight of the car freight.

$m_f$ = car's maximum weight

$= \frac{ 2000 \times 4.1}{3.4}\\\\= \frac{ 8.2\times 10^3}{3.4}\\\\= 2.41 \times 10^3$

$\boxed{m_f = 2.41 \times 10^3}$

8 0

2 years ago