Answer:
Incomplete question. Complete question is: An electric drill starts from rest and rotates with a constant angular acceleration. After the drill has rotated through a certain angle, the magnitude of the centripetal acceleration of a point on the drill is twice the magnitude of the tangential acceleration. Determine the angle through which the drill rotates by this point.
The answer is : Δ θ = 1 rad
Explanation:
Ok, so the condition involves the centripetal acceleration and the tangential acceleration, so let’s start by writing expressions for each:
Ac= centripetal acceleration At= tangential acceleration
Ac = V² / r At = r α
Because we have to determine the angle ultimately, therefore we should convert the linear velocity into angular velocity in the expression for centripetal acceleration
V = r ω
Ac = (r ω)² / r = r² ω² / r
Ac = r ω²
now that we have expressions for the centripetal and tangential acceleration, we can write an equation that expresses the condition given: The magnitude of the centripetal acceleration is twice the magnitude of the tangential acceleration.
Ac = 2 At
That is,
r ω² = 2 r α
it is equivalent to;
ω² = 2 α
now we have the relation between angular speed and angular acceleration, but we also need to determine the angular displacement as well. Therefore choose a kinematics equation that doesn’t involve time because time is not mentioned in the question. Thus,
ω² – ω°² = 2 α Δ θ
such that ω° = 0
and ω² = 2 α
therefore;
2 α - 0 = 2 α Δ θ
2 α = 2 α Δ θ
So the angle will be : Δ θ = 1 rad
Answer:
I think its 9.0397 Ohms
Explanation:
take the reciprocal of all the resistances: 1/15, 1/65, 1/35
then add them: = 151/1365
then reciprocal the answer: =1365/151
And chuck it on a calculator: =9.04 Ohms
I think this is right but I'm not entirely sure. Tell me if I'm right by the way!
Answer: The recoil speed is - 8.9604.
m/s.
Explanation: According to the Third Law of Newton, every action has an oppsite and equal reaction, and the Second Law of Newton, Force=mass·acceleration. Acceleration is a variation in velocity by any given time, so Force = mass·velocity·time.
Combining the two laws, there is : m1·v1 = - m2·v2. This is the Law of Conservation of Momentum.
Substituting and calculating:
v2 = - (
) · v1
v2 = - 
· 5.24.
v2 = - 8.9604.
The recoil speed of the thorium nucleus is - 8.9604.m/s.
Answer:
POSITIVE
Explanation:
The acceleration of an object is given by the rate of change of velocity.
u and v are initial and final velocities
If the final velocity is more than that of the initial velocity, the acceleration of the object is positive. It means positive acceleration occurs when an object speeds up. Hence, the correct option is (a) "positive".
