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DanielleElmas [232]

2 years ago

13

A bullet starting from rest accelerates uniformly at a rate of 1,250 meters per square second. What is the bullet's speed after

it has traveled 100 meters?

1 answer:

Tatiana [17]2 years ago

8 0

Answer:

125,000

Explanation:

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A 1500 kg car traveling at 20 m/s suddenly runs out of gas while approaching the valley shown in the figure. The alert driver im

geniusboy [140]

Answer:

v_f = 17.4 m / s

Explanation:

For this exercise we can use conservation of energy

starting point. On the hill when running out of gas

Em₀ = K + U = ½ m v₀² + m g y₁

final point. Arriving at the gas station

Em_f = K + U = ½ m v_f ² + m g y₂

energy is conserved

Em₀ = Em_f

½ m v₀ ² + m g y₁ = ½ m v_f ² + m g y₂

v_f ² = v₀² + 2g (y₁ -y₂)

we calculate

v_f ² = 20² + 2 9.8 (10 -15)

v_f = √302

v_f = 17.4 m / s

8 0

2 years ago

Two objects are dropped from rest from the same height. Object A falls through a distance Da and during a time t, and object B f

stiv31 [10]

Answer:

Da=(1/4)Db

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration due to gravity = 9.81 m/s²

When s = Da, t = t

$s=ut+\frac{1}{2}at^2\\\Rightarrow Da=0\times t+\frac{1}{2}\times a\times t^2\\\Rightarrow Da=\frac{1}{2}at^2$

When s = Db, t = 2t

$s=ut+\frac{1}{2}at^2\\\Rightarrow Da=0\times t+\frac{1}{2}\times a\times (2t)^2\\\Rightarrow Db=\frac{1}{2}a4t^2$

Dividing the two equations

$\frac{Da}{Db}=\frac{\frac{1}{2}at^2}{\frac{1}{2}a4t^2}=\frac{1}{4}\\\Rightarrow \frac{Da}{Db}=\frac{1}{4}\\\Rightarrow Da=\frac{1}{4}Db$

Hence, Da=(1/4)Db

3 0

2 years ago

Cindy exerts a force of 40 newtons and moves a chair 6 meters. Her brother Andy pushes a different chair for 6 meters while exer

sesenic [268]

Work formula:
W = F * d
F 1 = 40 N, d 1 = 6 m;
F 2 = 30 N; d 2 = 6 m.
W ( Cindy ) = 40 * 6 = 240 Nm
W ( Andy ) = 30 * 6 = 180 Nm
The difference of their amounts if work:
240 Nm - 180 Nm = 60 nm

hope it helps!

3 0

2 years ago

Which of the following forms of radiation can penetrate up to a 2-cm layer of skin tissue?

Dmitry_Shevchenko [17]

Answer:

d). X-rays

Explanation:

X -rays are also called photons. They are a packet of electro magnetic radiation. X rays originate from the shell of the electron. X rays are highly penetrating, and have a shorter wavelength than alpha particles and the beta particles. They are similar to the gamma rays which are also has a high penetrating power and easily pass through the human body.

Thus X rays can penetrate a skin tissue upto 2 cm thickness.

4 0

2 years ago

Read 2 more answers

A 120-kg refrigerator that is 2.0 m tall and 85 cm wide has its center of mass at its geometrical center. You are attempting to

Mademuasel [1]

To solve this problem it is necessary to apply the concepts related to Force of Friction and Torque given by the kinematic equations of motion.

The frictional force by definition is given by

$F= \mu mg$

Our values are here,

$\mu=0.3$

$m=120kg$

$g=9.8m/s^2$

Replacing,

$F=0.30*120*9.8 = 352.8N$

Consider the center of mass of the body half its distance from the floor, that is d = 0.85 / 2 = 0.425m. The torque about the lower farther corner of the refrigerator should be zero to get the maximum distance, then

$F*x = mg*d$

Re-arrange for x,

$x= \frac{mg*d}{F}$

$x= \frac{mg*d}{\mu mg}$

$x= \frac{d}{\mu}$

$x= \frac{0.425}{0.3}$

$x = 1.42m$

Then we can conclude that 1.42m is the distance traveled before turning.

6 0

2 years ago