Answer:
Because Bricks don't reflect. but mirrors reflect due to their lustre nature.
Explanation:
Answer:
4.2 m/s
Explanation:
Momentum is conserved.
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
(35 g) (9 m/s) + (75 g) (-7 m/s) = (35 g) (-15 m/s) + (75 g) v
315 g m/s − 525 g m/s = -525 g m/s + (75 g) v
315 g m/s = (75 g) v
v = 4.2 m/s
A, B, and C are all incorrect because they are talking about springs. I'm assuming you're talking about a 2 dimensional, side to side pendulum. In that case, the answer is D because as the pendulum goes up from one side, gravity accelerates it downward until it swings to the other side. If you're not talking about this type of pendulum, leave a comment and ill come back.
Recall the definitions of
• average velocity:
v[ave] = ∆x/∆t = (x[final] - x[initial])/t
Take the initial position to be the origin, so x[initial] = 0, and we simply write x[final] = s. So
v[ave] = s/t
• average acceleration:
a[ave] = ∆v/∆t = (v[final] - v[initial])/t
Assume acceleration is constant (a[ave] = a). Let v[initial] = u and v[final] = v, so that
a = (v - u)/t
Under constant acceleration, the average velocity is also given by
v[ave] = (v[final] + v[initial])/2 = (v + u)/2
Then
v[ave] = s/t = (v + u)/2 ⇒ s = (v + u) t/2
and
a = (v - u)/t ⇒ v = u + at
so that
s = ((u + at) + u) t/2
s = (2u + at) t/2
s = ut + 1/2 at²
It would be true. Excess radiation causes cancer.
