During a thunderstorm, you should crouch under a tree for shelter. a. True b. False

A ball is dropped off the side of a bridge. after 1.55 s, how far has it fallen

givi [52]

Answer:

38.64 feet

Explanation:

x=x0 + vx0t + 1/2axt2

x= 0 + 0 + 1/2 X 32.17 ft/sec2 X 1.55 sec2

x = 38.64 feet

7 0

2 years ago

A uniform ladder 5.0 m long rests against a frictionless, vertical wall with its lower end 3.0 m from the wall. The ladder weigh

DiKsa [7]

Answer:(a)360N,(b)171N,(c)2.702m

Explanation:

(a)Maximum Friction Force = $\mu \left ( N\right )=0.4\times \left ( 740+160\right )$

=360 N

$cos\theta =\frac{3}{5}$

$sin\theta =\frac{4}{5}$

(b)Moment about Ground Point

$740\times 1\times cos\theta +2.5\times 160\times cos\theta -N_15sin\theta$

$N_1tan\theta =1140$

$N_1=171 N$

$N_1=f=171 N$

(c)

$740\times x\times cos\theta +2.5\times 160\times cos\theta -N_15sin\theta$

Here maximum friction force can be 360 N

Therefore $N_1=360 N$

Where x is the maximum distance moved by man along the ladder

$360\times 5\times \frac{4}{3}=740x+160\times 2.5$

740x=2000

x=2.702m

5 0

2 years ago

Explain why atoms only emit certain wavelengths of light when they are excited. Check all that apply. Check all that apply. Elec

JulsSmile [24]

Answer:

Explanation:

Electrons are allowed "in between" quantized energy levels, and, thus, only specific lines are observed. FALSE. The specific lines are obseved because of the energy level transition of an electron in an specific level to another level of energy.

The energies of atoms are not quantized. FALSE. The energies of the atoms are in specific levels.

When an electron moves from one energy level to another during absorption, a specific wavelength of light (with specific energy) is emitted. FALSE. During absorption, a specific wavelength of light is absorbed, not emmited.

Electrons are not allowed "in between" quantized energy levels, and, thus, only specific lines are observed. TRUE. Again, you can observe just the transition due the change of energy of an electron in the quantized energy level

When an electron moves from one energy level to another during emission, a specific wavelength of light (with specific energy) is emitted. TRUE. The electron decreases its energy releasing a specific wavelength of light.

The energies of atoms are quantized. TRUE. In fact, the energy of all subatomic, atomic, and molecular particles is quantized.

7 0

2 years ago

Which action will decrease the gravitational force between two objects?

WITCHER [35]

Answer:

It’s D

Explanation:

6 0

2 years ago

What type of force is keeping this person from falling through the wall

Softa [21]

Answer:

Friction

Explanation:

Friction keeps things from sliding into things according to newton's laws

5 0

2 years ago