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3 years ago

A block slides down a rough ramp with a 30-degree incline as shown.

Physics

2 answers:

Studentka2010 [4]3 years ago

6 0

Answer: The first one

Explanation: My best guess is in the pic attached. Hope this helps.

Katen [24]3 years ago

5 0

Answer:

12 N to the right

Explanation:

EDGE 2021

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Which of the following statements are true?

inessss [21]

Answer:

a. If an object's speed is constant, then its acceleration must be zero.

FALSE

As we know that acceleration is defined as the rate of change in velocity

$a = \frac{d\vec v}{dt}$

so we can not say anything about the acceleration when speed is given to as and no information is given about velocity

b. If an object's acceleration is zero, then its speed must be constant.

TRUE

As we know that acceleration is defined as the rate of change in velocity

$a = \frac{d\vec v}{dt}$

Since we know that if acceleration is 0 then velocity must be constant and hence speed is also constant

c. If an object's velocity is constant, then its speed must be constant.

TRUE

Since velocity is constant then it shows that its magnitude and direction both are constant so its speed is also constant.

d. If an object's acceleration is zero, its velocity must be constant.

TRUE

As we know that acceleration is defined as the rate of change in velocity

$a = \frac{d\vec v}{dt}$

Since we know that if acceleration is 0 then velocity must be constant

e. If an object's speed is constant, then its velocity must be constant.

FALSE

Speed is just the magnitude so we can not say about its direction and hence if speed is constant then velocity may or may not change

7 0

3 years ago

A block of 250-mm length and 54 × 40-mm cross section is to support a centric compressive load P. The material to be used is a b

musickatia [10]

Answer:

P = 17.28*10⁶ N

Explanation:

Given

L = 250 mm = 0.25 m

a = 0.54 m

b = 0.40 m

E = 95 GPa = 95*10⁹ Pa

σmax = 80 MPa = 80*10⁶ Pa

ΔL = 0.12%*L = 0.0012*0.25 m = 3*10⁻⁴ m

We get A as follows:

A = a*b = (0.54 m)*(0.40 m) = 0.216 m²

then, we apply the formula

ΔL = P*L/(A*E) ⇒ P = ΔL*A*E/L

⇒ P = (3*10⁻⁴ m)*(0.216 m²)*(95*10⁹ Pa)/(0.25 m)

⇒ P = 24624000 N = 24.624*10⁶ N

Now we can use the equation

σ = P/A

⇒ σ = (24624000 N)/(0.216 m²) = 114000000 Pa = 114 MPa > 80 MPa

So σ > σmax we use σmax

⇒ P = σmax*A = (80*10⁶ Pa)*(0.216 m²) = 17280000 N = 17.28*10⁶ N

7 0

3 years ago

What happens when you place two magnets close together.

wlad13 [49]

They attract and stick together

3 0

3 years ago

Which organelle is the powerhouse of the cell, the site of cellular respiration? A) 2 - nucleus B) 5 - endoplasmic reticulum C)

Paladinen [302]

D) 9- mitochondria
Hope this helps :D

7 0

3 years ago

3.00 m^3 of water is at 20.0°C.

romanna [79]

Answer:

$\triangle V = 0.02484m^3$

Explanation:

Given

$V_1 = 3.00m^3$ --- initial volume

$T_1 = 20.0^oC$ --- initial temperature

$T_2 = 60.0^oC$ --- final temperature

$\gamma = 207*10^{-6$ --- coefficient of thermal expansion:

Required

The change in volume

To do this, we make use of cubic expansivity formula

$\triangle V = \gamma * V_2 * (T_2 - T_1)$

So, we have:

$\triangle V = 207 * 10^{-6} * 3.00 * (60.0 - 20.0)$

$\triangle V = 207 * 10^{-6} * 3.00 * 40.0$

$\triangle V = 0.02484m^3$

The volume will expand by $0.02484m^3$

7 0

3 years ago