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3 years ago

13

Một xe máy đang đi với v = 50,4 km/h bỗng người lái xe thấy có ổ gà trước mắt cách xe 24,5 m.Người ấy phanh gấp và xe đến ổ gà t

hì dừng lại. Gia tốc của xe là

1 answer:

Finger [1]3 years ago

3 0

Answer:

<h3>эмне, кечиресиз айым, бирок мен сиздин тилиңизди түшүнбөй</h3>

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a roller coaster begins at the top of a hill if it acelerates at the rate of 2 m/s2 and has a mass of 2000 kg what net force is

AlladinOne [14]

Answer:

$\boxed {\boxed {\sf 4000 \ Newtons }}$

Explanation:

Force can be found by multiplying the mass by the acceleration.

$F=m*a$

The mass of the roller coaster is 2000 kilograms and the acceleration is 2 meters per second squared.

$m= 2000 \ kg \\a= 2 \ m/s^2$

Substitute the values into the formula.

$F= 2000 \ kg * 2 \ m/s^2$

Multiply.

$F= 4000 \ kg*m/s^2$

1 kg*m/s² is equal to 1 N
Therefore our answer of 4000 kg*m/s² is equal to 4000 Newtons

$F= 4000 \ N$

The net force acting on the roller coaster is <u>4000 Newtons.</u>

7 0

3 years ago

What is the density of a piece of wood with a mass of 25 kg<br> and a volume of 0.0385 m³?

Orlov [11]

Answer:

649kg/m^3

Explanation:

Let p be the density of this particular object.

Formula for density:

$p = \frac{mass \: (in \: kg)}{volume \: (in \: {m}^{3}) }$

We can substitute the givenmass and volume to find density of the object.

$p = \frac{25kg}{0.0385 {m}^{3} } \\ = 649kg \: per \: {m}^{3}$

Therefore the density of this object is 649kg/m^3.

7 0

2 years ago

Tyrone, an 85-kg teenager, runs off the end of a horizontal pier and lands on a free-floating 130-kg raft that was initially at

Ghella [55]

Answer:u=4.04 m/s

Explanation:

Given

Mass m=85 kg

mass of Raft M=130 kg

velocity of raft and man v=1.6 m/s

Let initial speed of Tyrone is u

Conserving Momentum as there is no external Force

$mu=(M+m)v$

$85\times u=(85+130)\cdot 1.6$

$u=\frac{215}{85}\cdot 1.6$

$u=2.529\cdot 1.6=4.04 m/s$

4 0

3 years ago

You travel 23 meters north in 16 seconds, 5 meters south in 4 seconds, and 16 meters north in 18 seconds. Calculate your total d

dolphi86 [110]

Answer:

d: 44m

Δd:34

Explanation:

d: 23+5+16= 44m

Δd: 23-5+16= 34m

4 0

3 years ago

In 1976, the SR-71A, flying at 20 km altitude (T = –56 0C), set the official jet-powered aircraft speed record of 3530 km/hr (21

Lapatulllka [165]

To solve this problem we will apply the concepts related to the calculation of the speed of sound, the calculation of the Mach number and finally the calculation of the temperature at the front stagnation point. We will calculate the speed in international units as well as the temperature. With these values we will calculate the speed of the sound and the number of Mach. Finally we will calculate the temperature at the front stagnation point.

The altitude is,

$z = 20km$

And the velocity can be written as,

$V = 3530km/h (\frac{1000m}{1km})(\frac{1h}{3600s})$

$V = 980.55m/s$

From the properties of standard atmosphere at altitude z = 20km temperature is

$T = 216.66K$

$k = 1.4$

$R = 287 J/kg$

Velocity of sound at this altitude is

$a = \sqrt{kRT}$

$a = \sqrt{(1.4)(287)(216.66)}$

$a = 295.049m/s$

Then the Mach number

$Ma = \frac{V}{a}$

$Ma = \frac{980.55}{296.049}$

$Ma = 3.312$

So front stagnation temperature

$T_0 = T(1+\frac{k-1}{2}Ma^2)$

$T_0 = (216.66)(1+\frac{1.4-1}{2}*3.312^2)$

$T_0 = 689.87K$

Therefore the temperature at its front stagnation point is 689.87K

6 0

3 years ago