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2 years ago

What is the velocity of an upward moving 500kg elevator that has 4000 of energy

Physics

1 answer:

Mrrafil [7]2 years ago

6 0

Answer:

4 m/s

Step-by-Step Explanation:

E = mgh and h = E/mg

So if you put your numbers in the formula : h = 4000J/500 * 10

you will get h = 4/5 meters

use this , If the elevator moves from top to the ground in a constasnt acceleration you will have all energy (4000 J) transformed into acceleration to speed up its motion.

(All potential energy will be turned into movement energy). As explained in this formula;

mgh = mv²/2 , solve out (v) from the equation

v = √2gh = √2·10·4/5 (digits are together- not related to the problem, just for clarification) = 4 m/s

Answer the velocity of the elevator is

4 m/s

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A uniform solid cylinder with a radius of 10 cm and a mass of 3.0 kg is rotating about its center with an angular speed of 33.4

Bas_tet [7]

Answer:

0.092 J

Explanation:

Rotational kinetic energy is:

RE = ½ Iω²

where I is the moment of inertia and ω is the angular speed.

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RE = ¼ mr²ω²

Convert ω from rpm to rad/s.

33.4 rev/min × (2π rad/rev) × (1 min / 60 s) = 3.50 rad/s

Plug in values and solve:

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2 years ago

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3 years ago

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2 years ago

A 14.0 m uniform ladder weighing 490 N rests against a frictionless wall. The ladder makes a 63.0°-angle with the horizontal.

crimeas [40]

Answer:

Explanation:

Given:

length of ladder $r_L = 14m$

weight of ladder $F_L = 490N$

position of firefighter $r_F = 3.8m$

weight of firefighter $F_F = 820N$

angle of ladder $\alpha = 63$

Unknown:

force of the wall on the ladder $F_W$

force of friction on base of ladder $F_R$

normal force on base of ladder $F_N$

From the free body diagram of the sketch you get 3 equations:

$F_x = ma_x = F_W - F_R = 0\\ F_y = ma_y = F_N - F_F - F_L = 0\\ \tau _P = \overrightarrow{r} \times \overrightarrow{F} = r_FF_Fcos\alpha + \frac{1}{2}r_LF_Lcos\alpha - r_LF_Wsin\alpha = 0$