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Snezhnost [94]
3 years ago
11

A scientist in Northern California is studying the tree rings of a very old redwood tree. He notices that the oldest tree rings

are very narrow. As the rings move away from the center, he observes 15 rings that get wider and wider.
What can you determine about the climate during the 15-year period during which the tree rings grew wider?

The climate was warmer and wetter.
The climate was warmer and drier.
The climate was colder and drier.
The climate was colder and wette
Physics
2 answers:
Studentka2010 [4]3 years ago
5 0

Answer: colder and drier

Explanation:

Trees don’t grow well in wet climates, nor when they are cold. The wider the rings, the healthier the tree is. Since it was narrow and then wide, was bad climate and then good.

natali 33 [55]3 years ago
3 0

Answer:

A

Explanation:

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Which of these statements best describes how energy is transferred when an object experiences friction?
Slav-nsk [51]
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3 0
3 years ago
A 1000 kg elevator accelerates upward at 1.0 m/s2 for 10 m, starting from rest. a. How much work does gravity do on the elevator
cricket20 [7]

Answer:

a)= 98kJ

b)=108kJ

c) = 10kJ

Explanation:

a. The work that is done by gravity on the elevator is:

Work = force * distance  

= mass * gravity * distance

= 1000 * 9.81 * 10  

= 98,000 J

= 98kJ

b)The net force equation in the cable

T - mg = ma

T = m(g+a)

T = 1000(9.8 + 10)

T = 10800N

The work done by the cable is

W = T × d

= 10800N × 10

= 108000

=108kJ

c) PE at 10m = 1000 * 9.81 * 10 = 98,100 J  

Work done by cable = PE +KE  

108,100 J = KE + 98,100 J  

KE = 10,000 J

= 10kJ

=

7 0
3 years ago
Read 2 more answers
A 3-kg rock is thrown upward with a force of 200 N at a location where the local gravitational acceleration is 9.79 m/s2 . Deter
expeople1 [14]

Answer: 56.87m/s^{2}

Explanation:

If we make an analysis of the net force F_{net} of the rock that was thrown upwards, we will have the following:

F_{net}=F_{up}-W  (1)

Where:

F_{up}=200N is the force with which the rock was thrown

W is the weight of the rock

Being the weight the relation between the mass m=3kg of the rock and the acceleration due gravity g=9.79m/s^{2} :

W=m.g=(3kg)(9.79m/s^{2}) (2)

W=29.37 N (3)

Substituting (3) in (1):

F_{net}=200N-29.37 N  (4)

F_{net}=170.63 N  (5) This is the net Force on the rock

On the other hand, we know this force is equal to the multiplication of the mass with the acceleration, according to Newton's 2nd Law:

F_{net}=m.a  (6)

Finding the acceleration a:

a=\frac{F_{net}}{m}  (7)

a=\frac{170.63 N}{3kg} (8)

Finally:

a=56.87m/s^{2}

3 0
3 years ago
In which direction does a bag at rest move when a force of 20 newton's is applied from the right?
Olegator [25]

The bag moves to the left.

This is because of Newton's third law of motion that states:

For every action force on a body, there is an opposite and equal reaction force.

Thus pushing the bag from the right makes it move to the left.


8 0
4 years ago
The skateboarder in the drawing starts down the left side of the ramp with an initial speed of 6.4 m/s. Neglect nonconservative
aleksandrvk [35]

Answer:

2.087m

Explanation:

Using the formula for calculating the maximum height reached by an object expressed as:

H = u²/2g

u is the initial speed

g is the acceleration due to gravity

Given

u = 6.4m/s

g = 9.81m/s²

Substitute into the formula:

H =  6.4²/2(9.81)

H = 40.96/19.62

H = 2.087m

Hence the height h of the highest point reached by the skateboarder on the right side of the ramp is 2.087m

4 0
3 years ago
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