A child pushes a 75 N toy car across the floor. What is the mass of the car?

antiseptic1488 [7]

Answer:

E. Student 1 is correct, because as θ is increased, h is the same.

Explanation:

Here we have the object of a certain mass falling under gravity so the force acting on the it will depend on mass of the object and the acceleration due to gravity.

Mathematically:

$F=m.g$

As we know that the work done is evaluated as the force applied on a body and the displacement of the body in the direction of the force.

And for work we have:

$W=F.s\cos\theta$

where:

$s=$ displacement of the object

$\theta=$ angle between the force and displacement vectors

Given that the height of the object is same in each trail of falling object under the gravity be it a free-fall or the incline plane.

In case of free-fall the angle between the force is and the displacement is zero.
In case when the body moves along the inclined plane the force applied by the gravity is same because it depends upon the mass of the object. And the net displacement in the direction of the gravitational force is the height of the object which is constant in both the cases.

So, the work done by the gravitational force is same in the two cases.

6 0

3 years ago

A motorcycle of mass 100 kilograms slowly rolls off the edge of a cliff and falls for three seconds before reaching the bottom o

Jet001 [13]

Answer:

C) 3,000 kg m/s

Explanation:

We can consider the horizontal velocity of the motorcycle to be zero, since it rolls off the edge of the cliff very slowly. So, we only need to find the vertical velocity at the time of the impact with the ground.

The vertical velocity of the motorcycle at time t is given by (free-fall motion):

$v(t)=v_0 -gt$

where

$v_0=0$ is the initial vertical velocity (zero, since the motorcycle is not moving)

g = 9.8 m/s^2 is the acceleration due to gravity

t is the time

Since the motorcycle hits the ground after t = 3 seconds, we have

$v(3 s)=0-(9.8 m/s^2)(3 s)=-29.4 m/s$

And since we know its mass, m=100 kg, we can find its momentum:

$p=mv=(100 kg)(-29.4 m/s)=-2940 kg m/s \cdot -3000 kg m/s$

and the negative sign simply means downward direction.

8 0

3 years ago

A violin string that is 50.0 cm long has a fundamental frequency of 440 Hz. What is the

amid [387]

For a standing wave on a string, the wavelength is equal to twice the length of the string:
$\lambda=2 L$
In our problem, L=50.0 cm=0.50 m, therefore the wavelength of the wave is
$\lambda = 2 \cdot 0.50 m = 1.00 m$

And the speed of the wave is given by the product between the frequency and the wavelength of the wave:
$v=\lambda f = (1.00 m)(440 Hz)=440 m/s$

5 0

3 years ago

Read 2 more answers

A fish can travel 30km/h in still water. How long will it take to arrive 12km downstream in a river flowing 6km/h?

kodGreya [7K]

30 + 6 = 36

36/12 = 3

So, it would take it 3 hours to go 12 kms downstream.

Note that we added 30 and 6 because it was going downstream. If it was going upstream, then we would have had to subtract.

8 0

3 years ago

A sound source is located somewhere along the x-axis. Experiments show that the same wave front simultaneously reaches listeners

galina1969 [7]

Answer:

Explanation:

As the source is situated on x - axis , it must be situated in between the two listeners .

So the x coordinate of source is

(-7 + 3 )/2

= - 2 m

The equation of the wave- front will be that o a circle having centre at (-2,0)

and radius = distance between -2 and 3 , that is 5 m

equation of circle

=( x+2 )² + y² = 25

It cuts y axis when x = 0

Putting x = 0

4 + y² = 25

y² = 21

y = + √21 , or - √21

7 0

3 years ago