A box weighs 25N. How much mass does it have?

A 1.5kw vacuum cleaner is used for half an hour. Calculate its energy usage.

juin [17]

Answer:

its energy usage is 0.05

Explanation:

1.5kw/30=0.05

8 0

2 years ago

Can a body have increasing velocity with decreasing acceleration?

Sergio039 [100]

Sure. The acceleration may be decreasing, but as long as it stays
in the same direction as the velocity, the velocity increases.

I think you meant to ask whether the body can have increasing velocity
with negative acceleration. That answer isn't simple either.

If the body's velocity is in the positive direction, then positive acceleration
means speeding up, and negative acceleration means slowing down.

BUT ... If the body's velocity is in the negative direction, then positive
acceleration means slowing down, and negative acceleration means
speeding up.

I know that's confusing.

-- Take a piece of scratch paper, write a 'plus' sign at one edge and
a 'minus' sign at the other edge. Those are the definitions of which
direction is positive and which direction is negative.

-- Then sketch some cars ... one traveling in the positive direction, and
one driving in the negative direction. Those are the directions of the
velocities.

-- Now, one car at a time:
. . . . . first push on the back of the car, in the direction it's moving;.
. . . . . then push on the front of the car, against its motion.
Each push causes the car to accelerate in the direction of the push.

When you see it on paper, all the positive and negative velocities
and accelerations will come clear for you.

3 0

3 years ago

A mass free to vibrate on a level, frictionless surface at the end of a horizontal spring is pulled 35 cm from its equilibrium p

saul85 [17]

Answer:

0.67 s

Explanation:

This is a simple harmonic motion (SHM).

The displacement, $x$ , of an SHM is given by

$x = A\cos(\omega t)$

A is the amplitude and $\omega$ is the angular frequency.

We could use a sine function, in which case we will include a phase angle, to indicate that the oscillation began from a non-equilibrium point. We are using the cosine function for this particular case because the oscillation began from an extreme end, which is one-quarter of a single oscillation, when measured from the equilibrium point. One-quarter of an oscillation corresponds to a phase angle of 90° or $\frac{\pi}{4}$ radian.