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3 years ago

An 8.0-newton wooden block slides across a

1 answer:

7 0

If the block is sliding at constant velocity then its speed is constant. That means it is not losing any kinetic energy. There is no friction acting and the coefficient of kinetic friction is zero. Sadly, that choice of answer is not offered.

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(a) A light-rail commuter train accelerates at a rate of 1.35 m/s2 . How long does it take to reach its top speed of 80.0 km/h,

Mashcka [7]

Answer:

(a) Time t = 16.46 sec

(b) Time t =13.466 sec

Explanation:

(a) As the train starts from rest its initial velocity u = 0 m/sec

Acceleration $a=1.35m/sec^2$

Final speed v = 80 km/hr

$80km/hr=\frac{80\times 1000}{3600sec}=22.22m/sec$

From first equation of motion v =u+at

So $t=\frac{v-u}{a}=\frac{22.22-0}{1.35}=16.46 sec$

(b) Now initial speed u = 22.22 m/sec

As finally train comes to rest so final speed v=0 m/sec

Deceleration $a=1.65m/sec^2$

So $t=\frac{v-u}{a}=\frac{0-22.22}{-1.65}=13.466 sec$

Final velocity v = 0 m/sec

Time t = 8.30 sec

So acceleration is given by

$a=\frac{v-u}{t}=\frac{0-22.22}{8.3}=-2.6771m/sec^2$

As acceleration is negative so it is a deceleration

7 0

3 years ago

How did the astronomy of hipparchus and ptolemy violate the principles of early greek philosophers?

Mariana [72]

Answer: Hipparchus & Ptolemy believed sun and moon travel around circles with Earth in the middle (geocentric) while Plato and Aristotle believed Perfect unchanging heavens

Explanation: thus hipparchus and ptolemy violate early greek philosophy

8 0

3 years ago

Three pendulums all have the same length and start from the same height. The first pendulum is very light and has a mass of 67 g

vovikov84 [41]

Answer:

All three pendulum will attain same velocity

Explanation:

All three pendulum will attain same velocity irrespective of their mass difference in isolated system (means where air drag are negligible) and at same length

As you know when velocity is calculated we can not take mass into account.

3 0

3 years ago

A 50 kg mass is placed 2 meters from the fulcrum. To balance the lever, a second object is placed 4 meters

julia-pushkina [17]

Answer:

mass =25 kg

using clockwise moment = anticlockwise moment

8 0

3 years ago

The influence of blood vessel diameter on peripheral resistance is ________.

NeX [460]

Answer:

The influence of diameter of the blood vessel on peripheral resistance is significant because resistance is inversely proportional to the fourth power of the diameter.

Explanation:

The influence of diameter of the blood vessel on peripheral resistance is significant because the relation between the peripheral resistance and the diameter is given as, resistance is inversely proportional to the fourth power of the diameter. Thus, with small increase or decrease in the value of diameter, the peripheral resistance may vary by a significant amount.

6 0

3 years ago