Physics, 09.03.2021 21:40 mainray1792

Unit Test Question 2 of 25
Which of the following describes an object in dynamic equilibrium?
O A. A cheetah runs 15 m/s to the south.
B. A cat sits on a bed without moving.
C. A leopard slows down from 10 m/s to 5 m/s.
D. A dog runs in a circle at a speed of 8 m/s.

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Answer from: Quest

statement #3 on andre"s list is false.

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.

Answer from: Quest

Ohm's law tells you that i = v/r where v is equivalent voltage and r is equivalent resistance of the circuit
since all circuits have the same voltage, your question is really asking which circuit has the lowest total resistance, since the lower the resistance, the higher the current
circuit a has a resistance of 5 ohms; circuit c is in series so has a resistance of 10 ohms; circuit b is in parallel and therefore has a resistance of 2.5 ohms (review your notes on adding resistances in parallel and series); therefore b has the highest current

Answer from: Quest

Because they're in different places for this the temperature varies.

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Unit Test Question 2 of 25
Which of the following describes an object in dynamic equilibrium?...

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