Use the graph for both answers.

Physics

2 answers:

Makovka662 [10]4 years ago

5 0

First one is 6sec
The second one is positive acceleration

Natasha2012 [34]4 years ago

3 0

1. A. 6.00 sec

The graph shows the velocity of an object (y-axis) versus the time (x-axis). In order to find when the magnitude of the velocity reaches 36.00 km/h, we should find the time t (x-coordinate) at which the velocity (y-coordinate) is 36.

By looking at the graph, we see that this occurs when t=6.00 s.

2. A. positive acceleration

In a velocity-time graph like this one, the slope of the curve corresponds to the acceleration of the object. In fact, acceleration is defined as:

$a=\frac{\Delta v}{\Delta t}$

where $\Delta v$ is the variation of velocity and $\Delta t$ is the variation of time. We see that this quantity corresponds to the slope of the curve in the graph (in fact, $\Delta v$ represents the increment of the y coordinate, while $\Delta t$ represents the increment of the x coordinate). So, a positive slope means a positive acceleration: in this case, the slope is positive, so the acceleration is also positive.

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100 g of liquid nitrogen at its boiling point of 77 K is stirred into a beaker containing 500 g of 15°C water.

igomit [66]

Answer:

Option A: none

Explanation:

Specific heat capacity is the amount of heat energy required to raise the temperature of a substance per unit of mass.

From the question, the parameters given are; The heat of vaporization of nitrogen= 48 cal/g and that of water is 80 cal/g.

Using the formulae; Specific heat capacity,c= Q/ m× ∆T,----------–-----------------------------------------------------

STEP ONE: We will have to calculate all the energy numbers; 77k is approximately the boiling point of Nitrogen.

Energy required to decrease water from 15°C to 0°C = E(1).

0.1×10^3 g× 48 cal/gram..

= 4800 cal

Energy require to vaporize Nitrogen=E(2).

= 80 cal per gram×0.15(15-0)

= 180 cal

Energy required to decrease water from 15°C to 0°C is higher than that of the energy to vaporize Nitrogen, N2.

STEP 2: 180/4800× 15 = 0.5625

Therefore; 15-0.5625 =14.43

Answer= 14.43gC

8 0

4 years ago

Read 2 more answers

You are watching an archery tournament when you start wondering how fast an arrow is shot from the bow. Remembering your physics

spayn [35]

Answer:

$v_0 = 3.53~{\rm m/s}$

Explanation:

This is a projectile motion problem. We will first separate the motion into x- and y-components, apply the equations of kinematics separately, then we will combine them to find the initial velocity.

The initial velocity is in the x-direction, and there is no acceleration in the x-direction.

On the other hand, there no initial velocity in the y-component, so the arrow is basically in free-fall.

Applying the equations of kinematics in the x-direction gives

$x - x_0 = v_{x_0} t + \frac{1}{2}a_x t^2\\63 \times 10^{-3} = v_0t + 0\\t = \frac{63\times 10^{-3}}{v_0}$