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kumpel [21]
3 years ago
12

A person running down the hallway at a velocity of 4.2 m/s comes to a stop in a time of 1.8 seconds to avoid hitting the wall. W

hat was the acceleration of the person?
A.) 7.6 m/s/s
B.) -7.6 m/s/s
C.) 2.3 m/s/s
D.) -2.3 m/s/s
Physics
2 answers:
kumpel [21]3 years ago
6 0
Hshshshhshdhdhdhdhddhdhdhdhdhdh
adoni [48]3 years ago
3 0

Answer:

It's not -7.6

Explanation:

All I can tell you

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Rooms are fitted with ventilators to let the air move around. The phenomenon involved is:
Snezhnost [94]

Answer:

B. Convection

Explanation:

Convection is the process in which heat is transferred from one point to another by the actual movement of the material particles from a region of high temperature to a region of low temperature.

6 0
3 years ago
Read 2 more answers
shows a conical pendulum, in which the bob (the small object at the lower end of the cord) moves in a horizontal circle at const
Contact [7]

Answer:

a) T=0.40 N

b) T=1.9 s

Explanation:

Let's find the radius of the circumference first. We know that bob follows a circular path of circumference 0.94 m, it means that the perimeter is 0.94 m.

The perimeter of a circunference is:

P=2\pi r=0.94

r=\frac{0.94}{2\pi}=0.15 m

Now, we need to find the angle of the pendulum from vertical.

tan(\alpha)=\frac{r}{L}=\frac{0.15}{0.90}=0.17

\alpha=9.44 ^{\circ}

Let's apply Newton's second law to find the tension.

\sum F=ma_{c}=m\omega^{2}r

We use centripetal acceleration here, because we have a circular motion.

The vertical equation of motion will be:

Tcos(\alpha)=mg (1)

The horizontal equation of motion will be:

Tsin(\alpha)=m\omega^{2}r (2)

a) We can find T usinf the equation (1):

T=\frac {mg}{cos(\alpha)}=\frac{0.04*9.81}{cos(9.44)}=0.40 N

We can find the angular velocity (ω) from the equation (2):

\omega=\sqrt{\frac{Tsin(\alpha)}{mr}}=3.31 rad/s

b) We know that the period is T=2π/ω, therefore:

T=\frac{2\pi}{\omega}=\frac{2\pi}{3.31}=1.9 s

I hope it helps you!

8 0
3 years ago
When scientists want to determine the actual age of a fossil, they use_____________
zheka24 [161]

Answer:

Relative dating is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages. Absolute dating is used to determine a precise age of a fossil by using radiometric dating to measure the decay of isotopes, either within the fossil or more often the rocks associated with it.

4 0
3 years ago
An equilibrium is not changed by a change in pressure.<br> a. True<br> b. False
alexandr1967 [171]
An equilibruium is not changed by a changed in pressure. the answer is false
7 0
3 years ago
The value of acceleration due to gravity (g) on Pluto is about . 0.61 meters/second2. How much will an object that weighs 250 ne
Annette [7]
First, determine the mass of the object by dividing its weight on Earth by 9.8 m/s² as shown below,
                                   m = 250 N / 9.8 m/s² = 25.51 kg
Then, multiply the obtained mass by the acceleration due to gravity (g) on Pluto. 
                                  W (in Pluto) = (25.51 kg) x (0.61 m/s²)  = 15.56 N
Therefore, the object will only weigh 15.56 N. 
8 0
3 years ago
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