Answer:
<em>The student 1 pushes to the left, the student 2 pushed to the right</em>
Explanation:
<u>Mechanical Work</u>
The work done by a force F on an object moving a distance X and making an angle with the force is given by
If the force and the distance point in the same direction, the angle is 0 and the work is positive.
If the force and the distance point in opposite directions, the angle is 180° and the work is negative.
We know the glider moves to the left and the student 1 always does positive work, thus he must be pushing the block to the left to have the same direction.
The same can be applied to the second student who does a negative work when the block goes to the left, so he must be pushing to the right direction.
Summary: The student 1 pushes to the left, the student 2 pushed to the right
Answer:
20 J
Explanation:
Kinetic energy is given as half of the product of mass and the square of velocity of an object:
KE =
where m = mass = 40 kg
v = velocity = 1 m/s
Hence, Mary's kinetic energy is:
KE =
KE = 20 * 1 = 20 J
She has a kinetic energy of 20 J.
Answer:
Explanation:
Given
Length of rope
Weight of rope
weight density
Work done to lift rope 33 m
Answer:
The coefficient of kinetic friction is 0.13
Explanation:
Newton's second law states that the acceleration of an object is proportional to the net force on it, the factor of proportionality is the mass. So, we can express that law mathematically as:
(1)
With F the net force, m the mass and a the acceleration of the object. In our case we're interested on what's happening to the sled, then we have to analyze the forces on it, those forces are the weight and the normal force on the vertical direction and the pulling force and frictional force in the horizontal direction. So, because (1) is a vector equation we can express that in their vertical (y) and horizontal (x) components:
(2)
(3)
On y we have that the acceleration is zero because the sled is not moving upward or downward, remember that the net force on y is the weight (W) pointing downward and the normal force pointing upward:
Following the convention that positive is upward and negative downward, W=mg=(755)(-9.81):
(4)
Now on the x direction we have the sum of the forces is the pulling force (T) and friction force (f)
Choosing the direction where the horse is pulling F=1988N and the acceleration should be positive too, then:
The negative sign means it's in the opposite direction the horse is pulling
The frictional force is related with the coefficient of kinetic friction in the next way:
with μk the coefficient of kinetic friction, and n the normal force that we already found on (4), so we simply solve the last equation for μk:
Answer:
Spring's displacement, x = -0.04 meters.
Explanation:
Let the spring's displacement be x.
Given the following data;
Mass of each shrew, m = 2.0 g to kilograms = 2/1000 = 0.002 kg
Number of shrews, n = 49
Spring constant, k = 24 N/m
We know that acceleration due to gravity, g is equal to 9.8 m/s².
To find the spring's displacement;
At equilibrium position:
Fnet = Felastic + Fg = 0
But, Felastic = -kx
Total mass, Mt = nm
Fg = -Mt = -nmg
-kx -nmg = 0
Rearranging, we have;
kx = -nmg
Making x the subject of formula, we have;
Substituting into the formula, we have;
x = -0.04 m
Therefore, the spring's displacement is -0.04 meters.