The speed of the ball is always zero and the acceleration is always -g when it reaches the top of its motion. This is because when the ball is free, only gravity acts on it which is always downwards, hence g is the net acceleration and it is always negative. However the velocity does not direction change instantly, negative acceleration first slows down the ball with a positive velocity, until that point the ball keeps moving up, then the ball velocity becomes zero just before changing direction and becoming negative after which the ball will now go down along gravity. Hence the ball velocity is zero at the top (neither going up nor down). Mathematically this can be seen as velocity is the integration of acceleration.
Answer:
The magnitude of the torque on the loop due to the magnetic field is
.
Explanation:
Given that,
Diameter = 10 cm
Current = 0.20 A
Magnetic field = 0.30 T
Unit vector
We need to calculate the torque on the loop
Using formula of torque

Where, N = number of turns
A = area
I = current
B = magnetic field
Put the value into the formula


Hence, The magnitude of the torque on the loop due to the magnetic field is
.
Answer:
use of pesticides increasing insect resistance
Explanation:
Pesticides are the chemicals used to kill or stop the growth of insects or pests in crops and plants.
Pesticides are used from a very long time and repeated use of same pesticide allowed insects to get use to of it and evolve themselves in a way that they become resistant to these pesticide, so pesticide do not have any effect on insects.
Hence, the correct answer is "use of pesticides increasing insect resistance".
Answer:
v = 13.19 m / s
Explanation:
This problem must be solved using Newton's second law, we create a reference system where the x-axis is perpendicular to the cylinder and the Y-axis is vertical
X axis
N = m a
Centripetal acceleration is
a = v² / r
Y Axis
fr -W = 0
fr = W
The force of friction is
fr = μ N
Let's calculate
μ (m v² / r) = mg
μ v² / r = g
v² = g r / μ
v = √ (g r /μ)
v = √ (9.8 11 / 0.62)
v = 13.19 m / s
Answer:
Bounce 1 , pass 3, emb2
Explanation:
(By the way I am also doing that question on College board physics page) For the Bounce arrow, since it bumps into the object and goes back, it means now it has a negative momentum, which means a larger momentum is given to the object. P=mv, so the velocity is larger for the object, and larger velocity means a larger kinetic energy which would result in a larger change in the potential energy. Since K=0.5mv^2=U=mgh, a larger potential energy would have a larger change in height which means it has a larger angle θ with the vertical line. Comparing with the "pass arrow" and the "Embedded arrow", the embedded arrow gives the object a larger momentum, Pi=Pf (mv=(M+m)V), it gives all its original momentum to the two objects right now. (Arrow and the pumpkin), it would have a larger velocity. However for the pass arrow, it only gives partial of its original momentum and keeps some of them for the arrow to move, which means the pumpkin has less momentum, means less velocity, and less kinetic energy transferred into the potential energy, and means less change in height, less θangle. So it is Bounce1, pass3, emb2.