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Tresset [83]
3 years ago
15

a 2.1x10^3 kg car starts from rest at the top of the driveway that is sloped at an angle of 20 degree with the horizontal. an av

erage friction force of 4.0x10^3 N impedes the cars motion so that the cars speed at the bottom of the driveway is 3.8 m/s. what is the length of the driveway?

Physics
1 answer:
liberstina [14]3 years ago
8 0
Hopefully this will help you.

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TheE-field strength is 50,000 N/C inside a parallel plate capacitor with 2.0 mmspacing. A proton is released from rest at the po
Ghella [55]

Answer:

The speed is 138852.4 \frac{m}{s}

Explanation:

Electric field magnitude (E) and electric force magnitude (F) are related by the equation

F=Eq

with q the charge of the proton (1.61\times10^{-19} C). Because between parallel plates electric field is almost constant, electric force is constant too:

F=(50000)(1.61\times10^{-19})=8.05\times10^{-15}N

because electric force is constant, then by Newton's second law acceleration (a) is constant too, it is:

a=\frac{F}{m}

with m the mass of the proton (1.67\times10^{-27} kg):

a=\frac{8.05\times10^{-15}}{1.67\times10^{-27}}= 4.82\times10^{12}\frac{m}{s^{2}}

Now with this constant acceleration we can use the kinematic equation

v^{2}=v_{0}^{2}+2ad

with v the final speed, v_i the initial velocity that is zero (because proton starts at rest) and d is the distance between the plates, so:

v=\sqrt{2ad}=\sqrt{2(4.82\times10^{12}\frac{m}{s^{2}})(2.0\times10^{-3}m)}

v=138852.4 \frac{m}{s}

5 0
3 years ago
Peter was holding a Human Physiology textbook that weighs about 4lbs with his non- writing arm for one minute. His elbow remaine
Slav-nsk [51]

Answer:

a

When peter held the book for one minute the rate at which motor unites are fired increase steeply but as the duration increases the increese in the rate at which it is being fired becomes linear so the number of activated motors stay the same but are being activated at a more rapidly

b

The same motors are activated whilest he is hold the book for 2 minutes this is because for peter to hold the book in one fixed position one specific motor units  need to be activated

Note changing the motor unites would change the positon of the hand

Explanation:

4 0
3 years ago
Can anyone tell me how to read a micrometer screw gauge I want very clear instructions.
Natalka [10]

Explanation:

Things you need to know:

Accuracy refers to the maximum error encountered when a particular observation is made.

Error in measurement is normally one-half the magnitude of the smallest scale reading.

Because one has to align one end of the rule or device to the starting point of the measurement, the appropriate error is thus twice that of the smallest scale reading.

Error is usually expressed in at most 1 or 2 significant figures.

Tape

Equipment: It is made up of a long flexible tape and can measure objects or places up to 10 – 50 m in length. It has markings similar to that of the rigid rule. The smallest marking could be as small as 0.1 cm or could be as large as 0.5 cm or even 1 cm.

How to use: The zero-mark of the measuring tape is first aligned flat to one end of the object and the tape is stretched taut to the other end, the reading is taken where the other end of the object meets the tape.

Ruler

Equipment: It is made up of a long rigid piece of wood or steel and can measure objects up to 100 cm in length. The smallest marking is usually 0.1 cm.

How to use: The zero-end of the rule is first aligned flat with one end of the object and the reading is taken where the other end of the object meets the rule.

Vernier Caliper

Equipment: It is made up of a main scale and a vernier scale and can usually measure objects up to 15 cm in length. The smallest marking is usually 0.1 cm on the main scale.

It has:

a pair of external jaws to measure external diameters

a pair of internal jaws to measure internal diameters

a long rod to measure depths

How to use: The jaws are first closed to find any zero errors. The jaws are then opened to fit the object firmly and the reading is then taken.

Micrometer Screw Gauge

Equipment: It is made up of a main scale and a thimble scale and can measure objects up to 5 cm in length. The smallest marking is usually 1 mm on the main scale (sleeve) and 0.01 mm on the thimble scale (thimble). The thimble has a total of 50 markings representing 0.50 mm.

It has:

an anvil and a spindle to hold the object

a ratchet on the thimble for accurate tightening (prevent over-tightening)

How to use: The spindle is first closed on the anvil to find any zero errors ( use the ratchet for careful tightening). The spindle is then opened to fit the object firmly (use the ratchet for careful tightening) and the reading is then taken.

5 0
3 years ago
You drop a small ball, and then a second small ball. When you drop the second ball, the distance between them is 3 cm. What stat
Alja [10]

Answer:

c) The distance between the balls increases.

Explanation:

If you drop the balls at the same time, regardless of their masses they accelerate equally, since they will be in free fall.

However, if you drop one of the balls earlier, then that ball will gain velocity, whereas the second ball has zero initial velocity. At the time the second ball is dropped, both balls have the same acceleration but different initial velocities.

According to the below kinematics equation:

x = v_0t + \frac{1}{2}at^2

The initial velocity of the first ball will make the difference, and the first ball will travel a greater distance than the second ball. Hence, their distance increases.

3 0
3 years ago
2) Two railway tracks are parallel to west east direction. Along one track, train A moves with a speed of 45 m/s from
Natalija [7]

Answer:

105 m/s

Explanation:

Given that the speed of train A, V_A = 45 m/s from west to east.

Speed of train B, V_B = 60 m/s from east to west.

Train B is moving in the opposite direction with respect to the speed of train A. Assuming that the speed from east to west direction is positive.

So, the speed of train A from east to west= - 45 m/s

The speed of train B w.r.t train A = V_B - V_A=60-(-45)=60+45=105 m/s

Hence, the speed of train B w.r.t train A is 105 m/s from east to west.

5 0
3 years ago
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