Answer:
work done by tension force on the twirled stone must be ZERO always
Explanation:
As we know that work done by a force on an object is given as


here we know that
= angle between force and displacement
now we know that tension in the string and displacement of the object is always perpendicular to each other when the rock is twirled in circular path.
so we can say for this motion of the stone

so work done by tension force on the twirled stone must be ZERO always
The traveled distance of the car from the initial point is (4+7) Km, i.e., 11 Km.
Speed/ velocity/ how fast the car is moving!
Hope this assists you!
Answer:
2.1 m/s²
Explanation:
By definition, the angular acceleration, is equal to the rate of change of the angular velocity, ω:
α = Δω / Δt (1)
By definition of the angular velocity, we can express the linear velocity, v, as follows:
v = ω*r⇒ Δv = Δω*r (2)
Replacing Δω, from (1) in (2), we get:
Δv = α*Δt*r⇒ Δv/Δt = α*r (3)
By definition of linear acceleration, we can write the following expression;
a = α*r
For a point on the edge of the wheel, the linear acceleration is tangent to the rim, and is equal to the product of the angular acceleration times the distance to the center, which for a point on the edge of the wheel, is just the radius:
⇒ a = 7 rad/sec²*0.3m = 2.1 m/s²
Direct rotation is your answer .-.