Answer:
The correct option is D
Explanation:
This question is incomplete because of the absence of the setup which as been attached below. The setup shows/determines/tests the friction of wood (which is a block material), since Jerry wants to test the friction between different types of materials, he will have to replace the wooden block with another type of block material of choice so as to determine the friction of that also.
In order to have a comprehensive experiment, Jerry can use 4-5 different types of block material in the course of the experiment.
Answer:
is the initial velocity of tossing the apple.
the apple should be tossed after 
Explanation:
Given:
- velocity of arrow in projectile,

- angle of projectile from the horizontal,

- distance of the point of tossing up of an apple,

<u>Now the horizontal component of velocity:</u>



<u>The vertical component of the velocity:</u>



<u>Time taken by the projectile to travel the distance of 30 m:</u>



<u>Vertical position of the projectile at this time:</u>



<u>Now this height should be the maximum height of the tossed apple where its velocity becomes zero.</u>


is the initial velocity of tossing the apple.
<u>Time taken to reach this height:</u>



<u>We observe that </u>
<u> hence the time after the launch of the projectile after which the apple should be tossed is:</u>



Answer: The mass of the sculpture is 11.8kg
Explanation:
Using the equation of fundamental frequency of a taut string.
f = (1/2L)*√(T/μ) .... (Eqn1)
Where
f= frequency in Hertz =80Hz
T = Tension in the string = Mg
M represent the mass of the substance (sculpture) =?
g= 9.8m/s^2
L= Length of the string=90cm=0.9m
μ= mass density = mass of string /Length of string
mass of string =5g=0.005kg
L=0.9m
μ=0.005/0.9 = 0.0056kg/m
Using (Eqn1)
80= 1/(2*0.9) √(T/0.0056)
144= √(T/0.0056)
Square both sides
20736= T/0.0056
T= 116.12N
Recall that T =Mg
116.12= M * 9.8
M=116.12/9.8
M= 11.8kg
Therefore the mass of the sculpture is 11.8kg
The force per unit of length between two wires carrying current is

where I1 and I2 are the currents in the two wires, while r is the distance between them.
We can see from the formula that the force is proportional to the product between I1 and I2:

so, if we double both I1 and I2, we get a factor 4:

so, the force between the wires will be 4 times the original value.
1kg = 1000000000 micrograms
I hope it helps you ;)