<span><span>Velocity is a vector, and the initial and final ones are in opposite directions.
There must have been acceleration in order to change the direction of motion.</span>
A) No. The initial and final velocities are the same.
This is all wrong, and not the correct choice.
It's "Yes", and the initial and final velocities are NOT the same.
B) Yes. The ball had to slow down in order to change direction.
This is poor, and not the correct choice.
The "Yes" is correct, but the explanation is bad.
Acceleration does NOT require any change in speed.
C) No. Acceleration is the change in velocity. The ball's velocity is constant.
This is all wrong, and not the correct choice.
It's "Yes", there IS acceleration, and the ball's velocity is NOT constant.
D) Yes. Even though the initial and final velocities are the same, there is a change in direction for the ball.
This choice is misleading too.
The "Yes" is correct ... there IS acceleration.
The change in direction is the reason.
The initial and final velocities are NOT the same. Only the speeds are.
</span>
Answer:
4 A
Explanation:
V = IR, where V=voltage, I=current, R=resistance. This is Ohm's Law. (remember that for units V = volts, Ω = ohms, A = amperes.)
V = IR
12 V = I * 3 Ω
12/3 = I
<u>I = 4 A</u>
Answer:
(a) 328 Nm
(b) 79.35 Nm
Explanation:
N = =150, side = 17.5 cm = 0.175 m, i = 42 A, B = 1.7 T
A = side^2 = 0.175^2 = 0.030625 m^2
(a) Torque = N x i x A x B x Sinθ
For maximum torque, θ = 90 degree
Torque = 150 x 42 x 0.030625 x 1.7 x Sin 90
Torque = 328 Nm
(b) θ = 14 degree
Torque = 150 x 42 x 0.030625 x 1.7 x Sin 14
Torque = 79.35 Nm
(a) As the car is moving with constant velocity, it means the rate change of velocity does not change, therefore the average acceleration of the car is zero.
Thus, there is no acceleration, when velocity is constant.
(b) Average acceleration,
Here, v is final velocity and u is the initial velocity and 
is the time interval.
As twelve seconds later, the car is halfway around the track and traveling in the opposite direction with the same speed, therefore
Thus, the average acceleration of the car is 
in the direction to the left.
Answer:
From 0 -4 seconds the acceleration is positive. (The graph is going upwards.)
From 6-10 seconds the acceleration is negative. (The graph is going downwards.)
