Physics, 07.09.2019 03:20 gamallopatty

Aclock has an hour hand of length 2.4 cm and a minute hand of length 3.8 cm. (a) calculate the position and velocity of the hour hand at noon. (b) calculate the position and velocity of the minute hand at 12: 15.

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At 12:00 the hour hand it's located at 0 degrees and its tip travels with a velocity of 1.26 cm/hour, approximately.At 12:15 the minute hand it's located at 90 degrees and its tip travels with a velocity of 23.88 cm/hour, approximately.

Explanation:

Position is given by an angle, in this case starting from the 12:00 mark and opening clockwise.

At noon, the the hour hand is located at the 12:00 mark, so its position is 0 degrees; and it has an angular velocity of (2π)/(12 hour) = π/(6 hour). So its tip travels with linear velocity of (2.4 cm) * π/(6 hour) ≅ 1.26 cm/hour.At 12:15, the minute hand is located at the 3 hour mark, so its position is 90 degrees or π/2; and it has an angular velocity of (2π)/(1 hour) = 2π/hour. So its tip travels with linear velocity of (3.8 cm) * 2π/hour ≅ 23.88 cm/hour.

Answer from: Quest

a=d/t

a="triangle"v/t

explanation:

a = acceleration

Answer from: Quest

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

$f\alpha \frac{dp}{dt}$

⇒ $f= k \frac{dp}{dt}$

here k is the proportionality constant whose value is 1.

$f=\frac{dp}{dt}$

$f= \frac{d[mv]}{dt}$

$f= m\frac{dv}{dt} +v\frac{dm}{dt}$

$f=ma+v\frac{dm}{dt}$ [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.

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Aclock has an hour hand of length 2.4 cm and a minute hand of length 3.8 cm. (a) calculate the posit...

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