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3 years ago

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Jody drives 120 miles south from Kingston, NY to Princeton, NJ. If she drives 60 mph, how long will it take her to make the trip

?
cannot be determined
1 hour
2 hours
4 hours
people keep giving really stupid answers-

2 answers:

Bas_tet [7]3 years ago

6 0

sorry if its wrong but 2 hours??

xxTIMURxx [149]3 years ago

3 0

2 hours cause 60 mph then 2 hours

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An object starts at rest then accelerates at a rate of 5m/s^2 for 1 second and then 2m/s^2 for 2 seconds. What is the average ac

inn [45]

Acceleration = (change in speed) / (time for the change)

-- during the first second, the object increases its speed to

(5 m/s²) · (1 s) = 5 m/s .

-- During the next 2 seconds, the object increases its speed by

(2 m/s²) · ( s) = 4 m/s

So at the end of the whole 3 seconds, its speed is (5 m/s) + (4 m/s) = 9 m/s

-- Over the whole time, its speed has changed from zero to 9 m/s.

Acceleration = (change in speed) / (time for the change)

Acceleration = (9 m/s) / (3 sec)

<em>Acceleration = 3 m/s²</em>

7 0

3 years ago

Billiard ball A of mass mA = 0.125 kg moving with speed vA = 2.80 m/s strikes ball B, initially at rest, of mass mB = 0.140 kg .

lianna [129]

Answer:

V=1.309

β= -41.997

Explanation:

Law Newton's conservation motion

Axis x

$m_{1}*v_{x1}+m_{2}*v_{x2}=m_{1}*v_{fx1}+m_{2}*v_{fx2}\\v_{x1}=2.8\frac{m}{s}\\v_{x2}=0 \frac{m}{s}\\m_{1}=0.125kg\frac{m}{s}\\m_{2}=0.140kg\frac{m}{s}\\0.125kg*2.8\frac{m}{s}+0.14kg*0=0.125kg*2.10\frac{m}{s}*cos(30) +0.14kg*v_{fx2}\\0.35 \frac{kg*m}{s} =0.125kg*1.81\frac{m}{s}+0.14kg*v_{fx2}\\v_{fx2}=\frac{0.12\frac{kg*m}{s} }{0.14kg} \\v_{fx2}=0.876 \frac{m}{s}$

Axis y

$m_{1}*v_{y1}+m_{2}*v_{y2}=m_{1}*v_{fy1}+m_{2}*v_{fy2}$

$v_{y1} =0\\v_{y2} =0$

$0=m_{1}*v_{fy1} +m_{2}*v_{fy2} \\v_{fy2}=-\frac{m_{1}*v_{fy1} }{m_{2}}\\ v_{fy2}=-\frac{0.125kg*2.10*sen(30)\frac{m}{s}}{0.14kg}\\v_{fy2}= -0.937\frac{m}{s}$

So the velocity $v_{f2}$

$v_{f2}=\sqrt{v_{fx2}^{2} +v_{fy2}^{2} } \\v_{f2}=\sqrt{0.876^{2} +0.983^{2} } \\v_{f2}=1.309\frac{m}{s}$

The angle can be find using both velocity factors

$\alpha =tanx^{-1}*\frac{v_{fx2}}{v_{fy2}} \\\alpha =tanx^{-1}*\frac{0.876}{-0.973}\\ \alpha =tanx^{-1}*\\ \alpha =-41.997$

Check:

$m_{1}*v_{x1}+m_{2}*v_{x2}=m_{1}*v_{fx1}+m_{2}*v_{fx2}$

$0.125*2.80=0.125*2.1*cos(30)+0.14*1.03*cos(-41.997)\\0.35=0.227+0.107\\$

0.35≅0.3489

4 0

3 years ago

You replace a 100 W incandescent lightbulb with a 22 W CFL bulb. If you leave your lights on 24 hours a day, how much energy are

crimeas [40]

100 watts = 100 joules per second
22 watts = 22 joules per second
Saving = 78 joules per second

1 hour = 3,600 seconds
24 hours = 86,400 seconds

(78 joules/sec) x (86,400 sec) = 6,739,200 joules

5 0

3 years ago

If the slope of a line on a speed-time graph is 0 and it is not on the x-axis, what is the object doing?

Zinaida [17]

It is moving at a constant speed, not accelerating.

4 0

3 years ago

If you were to drop a rock from a tall building, assuming that it had not yet hit the ground, and neglecting air resistance, aft

elena-14-01-66 [18.8K]

Since the object is dropped from some height so its initial speed must be zero

acceleration of the object is due to gravity

so we can use kinematics to find the time it will take to drop by x = 22 m

$\delta x = v_i * t + \frac{1}{2}at^2$

$22 = 0 + \frac{1}{2}*9.8*t^2$

$t = 2.12 s$

Now the speed after 2.12 s will be given as

$v_f = v_i + at$

$v_f = 0 + 9.8 * 2.12$

$v_f = 20.8 m/s$

so above is the speed and time

5 0

3 years ago