Answer:
TRUE
Explanation:
Low mass stars last lots longer.
Answer:
50 N
Explanation:
Since the refrigerator doesn’t move, that means the force of friction equals the amount of force the child exerts on the fridge. If the friction force were greater than the force by the child, the fridge would start accelerating towards the child. If it were less than the force the child exerted, the fridge would start accelerating away from the child. Therefore, the net force must be 0, in this case, the friction force is equal to the force the child exerted, for it to stay at rest (as Newton’s First Law stated).
I hope this helps! :)
Answer: a. Place the object on one side of a lever at a known distance away from the fulcrum. Place known masses on the other side of the fulcrum so that they are also paced on the lever at known distance from the fulcrum. Move the known masses to a known distance such that the lever is in static equilibrium.
d. Place the object on the end of a vertically hanging spring with a known spring constant. Allow the spring to stretch to a new equilibrium position and measure the distance the spring is stretched from its original equilibrium position.
Explanation:
The options are:
a. Place the object on one side of a lever at a known distance away from the fulcrum. Place known masses on the other side of the fulcrum so that they are also paced on the lever at known distance from the fulcrum. Move the known masses to a known distance such that the lever is in static equilibrium.
b. Place the object on a surface of negligible friction and pull the object horizontally across the surface with a spring scale at a non constant speed such that a motion detector can measure how the objects speed as a function of time changes.
c. Place the object on a surface that provides friction between the object and the surface. Use a surface such that the coefficient of friction between the object and the surface is known. Pull the object horizontally across the surface with a spring scale at a nonconstant speed such that a motion detector can measure how the objects speed as a function of time changes.
d. Place the object on the end of a vertically hanging spring with a known spring constant. Allow the spring to stretch to a new equilibrium position and measure the distance the spring is stretched from its original equilibrium position.
Gravitational mass simply has to do with how the body responds to the force of gravity. From the options given, the correct options are A and D.
For option A, by balancing the torque, the mass can be calculated. Since the known mass and the distance has been given here, the unknown mass can be calculated.
For option D, here the gravitational force can be balanced by the spring force and hence the mass can be calculated.
Answer:
c. expanded polyurethane
Explanation:
Thermal performance of a building fabric is measured in terms of heat loss and is expressed as U-value or R-value. U-value is the rate of heat transferred through a structure divided by the difference in temperature across the structure with a unit of measurement of W/m²K.You can calculate the U-value of a by getting the reciprocal of the sum of thermal resistances , R, making the building material.
If you have the value of R, then U=1/R
Material size R U
plywood 1" 1.25 0.8
Poured concrete 2" 0.99 1.010
Expanded polyurethane 1" 6.5 0.1538
Asbestos shingles 1" 0.03 33.33
The material with lowest U-value is expanded polyurethane
