Answer:
The average drag force is 1.206 (-i) N
Explanation:
You have to apply the equations of<em> Impulse</em>:
I=FmedΔt
Where I and Fmed (the average force) are vectors.
The Impulse can also be expressed as the change in the <em>quantity of motion</em> (vector P)
I=P2-P1
P=mV (m is the mass and v is the velocity)
You can calculate the quantity of motion at the beggining and at the end of the given time:
Replace the mass in kg, dividing the mass by 1000 to convert it from g to kg.
P1=(0.179kg)(30.252m/s) i= 5.414 i kg.m/s
P2=0.179kg)(28.452m/s) i = 5.092 i kg. m/s
Where i is the unit vector in the x-direction.
Therefore:
I= 5.092 i - 5.414 i = -0.322 i
The average drag force is:
Fmed= I/Δt = -0.322 i/ 0.267s = -1.206 i N
Answer:
0 (Zero)
Explanation:
Definition of work done states that ,
Work done on an object is the force applied on that object in the direction of Displacement of the object .
means that ,
W = F.dS (Dot product of Force and displacement)
When the wall is acted upon by the force of 20 N , Wall does not move ,
Thus , displacement of the wall is zero.
So, W = 20×0 = 0.
Thus, Work done on the wall is zero.
Since the block is not moving, it only has potential energy and no kinetic energy.
energy = mgh = 8 x 9.81 x 20 = 1569.6J
Answer:
a. Temperatures increase can change a solid to a liquid, but cannot change a liquid to a solid
b. The particles in a solid are much closer together than the particles in a liquid.
Explanation:
Any material expands when heated and contracts when cooled. So, when a body is heated to a particular temperature, it starts melting and changes into a liquid.
As the material expands the distance between the atoms or molecules increases and it will become a liquid. So it can move around the material. It doesn't become solid on further heating. But water is an exception where it contracts when heated from 0° to 4° C.
In solids, these atoms or molecules are closely packed. It is rigidly fixed.
The solid, as well as the liquid, has a definite volume, but the liquid does not have a definite shape.
Answer:
Spring constant = YA / L
Explanation:
Let F be the force being applied on cross sectional area A of metal bar due to which an extension of ΔL is obtained in the wire of length L then
stress = F / A
strain = ΔL /L
Young's modulus = ( F / A ) / (ΔL /L)
Y = ( F L / A ΔL )
( F / ΔL ) = ( YA / L )
Spring constant = ( F / ΔL )
Spring constant = YA / L
