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2 years ago

8

A car speeds up as it rolls down a hill. Which is this an example of? A. positive acceleration B. negative acceleration C. relat

ive velocity

1 answer:

alina1380 [7]2 years ago

4 0

I believe it is A. positive acceleration since it is speeding up

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A force of 45 N is applied tangentially to the rim of a solid disk of radius 0.12 m. The disk rotates about an axis through its

bearhunter [10]

Answer:

Mass of the disk will be 2.976 kg

Explanation:

We have given force F = 45 N

Radius of the disk r = 0.12 m

Angular acceleration $\alpha =140rad/sec^2$

We know that torque $\tau =I\alpha$

And $\tau =Fr$

So $Fr=I\alpha$ , here I is moment of inertia

So $50\times 0.12=I\times 140$

$I=0.0428kgm^2$

We know that moment of inertia $I=\frac{1}{2}mr^2$

So $0.0428=\frac{1}{2}\times m\times 0.12^2$

m = 2.976 kg

6 0

2 years ago

You serve a volleyball with a mass of 2.1 kg. The ball leaves your hand with a speed of 30 m/s. The ball has—— energy. Calculate

Slav-nsk [51]

Answer:

945 j

Explanation:

You have just given the ball kinetic energy, which is given by the following equation:

KE= 1⁄2 m v2 = 1⁄2 (2.1 kg)(30 m/s)2 = 945 Joules

3 0

3 years ago

Hooke's law describes a certain light spring of unstretched length 33.6 cm. when one end is attached to the top of a doorframe a

masha68 [24]

Missing question: "What is the spring's constant?"

Solution:
The object of mass m=6.89 kg exerts a force on the spring equal to its weight:
$F=mg=(6.89 kg)(9.81 m/s^2)=67.6 N$
When the object is attached to the spring, the displacement of the spring with respect to its equilibrium position is
$\Delta x=43.2 cm-33.6 cm=9.6 cm=0.096 m$
And by using Hook's law, we can find the constant of the spring:
$k= \frac{F}{\Delta x}= \frac{67.6 N}{0.096 m}=704.2 N/m$

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2 years ago

PLEASE IM TIMED! GIVE BRAINLIEST OF U ANSWER THESE 2 QUESTION!!

erastovalidia [21]

Answer:

thermal
true

Explanation:

hope this helps!

7 0

2 years ago

Read 2 more answers

Why doesn’t a machine that increases force break the law of conservation of energy?

USPshnik [31]

Answer:

A machine in which work input equals work output. energy can be used to do work, work can be used to transfer energy. The change in the kinetic energy of an object is equal to the net work done on the object.

hope this helps

8 0

2 years ago