Answer:
b) the second at the doorknob.
Explanation:
The torque applied by a force is given by the equation
where
is the torque
is the component of the force perpendicular to the direction between the axis of rotation and the point of application of the force
d is the arm (the distance between the axis of rotation and the point of application of the force)
In this problem, we have two equal forces F both applied perpendicular to a door, so
The first force is applied at the midpoint of the door; if we call L the width of the door, then the arm of this force is 
, so the torque applied by this first force is
The 2nd force instead is applied at the doorknob, so the arm in this case is L:
d = L
So, the torque exerted by the second force is
Therefore, we see that the 2nd force exerts a greater torque.
Answer:
θ₁ = 35.32°
Explanation:
given,
refractive index of medium 1 = n₁ = 1.75
refractive index of medium 2 = n₂ = 1.24
condition to describe the refracted angle
...(1)
Using Snell's Law
n₁ sin θ₁ = n₂ sin θ₂
θ₁ , θ₂ is the angle of incidence and refractive index
n₁. n₂ is the refractive index medium 1 and medium 2
1.75 x sin θ₁ = 1.24 x sin θ₂
From equation (1)
1.75 x sin θ₁ = 1.24 x sin (90-θ₁)
1.75 sin θ₁ = 1.24 cos θ₁
tan θ₁ = 0.708
θ₁ = 35.32°
Hence, angle of incidence is equal to θ₁ = 35.32°
The old view of the solar system was geocentric, which means that people believed that the Earth is the center of the universe. However, with the discoveries of Galileo, Newton, and Copernicus, evidence was brought forth that the solar system is actually heliocentric, which means that the sun is the center of the universe.
Answer:
When truck is at rest while student is under motion
Explanation:
Since it is obvious that the mass of a truck is more than that of a student, we know that momentum is a product of mass and velocity
P=mv where m represent mass, v is velocity. When the student has more speed than that of truck, he exerts more momentum. The only way a student can exert more momentum is by having more speed while the truck is at rest. In such case, the momentum of truck will be zero while momentum of student will have a value
Rate of change of momentum = impact force
(m*v-m*u)/t = F
4000*20/t = 80000 (note: v is zero as it stopped)
<span>soo, t = 1 sec</span>
