Answer:
The correct answer is B
Explanation:
The moment of an object is the product of its mass by velocity, it is described by the equation
p = mv
In this problem they give us the most body and speeds before and after the crash. We must define an environment with both bodies so that the forces during the crash have been internalized and the moment is preserved
Δp = pf -p₀
Δp = m 
- m v₀
Δp = 2 9 -2 1.5
ΔP = 14.8 m/s
The correct answer is b
A) 
The angular acceleration of the wheel is given by
where
is the initial angular velocity of the wheel (initially clockwise, so with a negative sign)
is the final angular velocity (anticlockwise, so with a positive sign)
is the time interval
Substituting into the equation, we find the angular acceleration:
And the acceleration is positive since the angular velocity increases steadily from a negative value to a positive value.
B) 3.6 s
The time interval during which the angular velocity is increasing is the time interval between the instant 
where the angular velocity becomes positive (so, 
) and the time corresponding to the final instant 
, where 
. We can find this time interval by using
And solving for 
we find
C) 2.4 s
The time interval during which the angular velocity is idecreasing is the time interval between the initial instant 
when 
) and the time corresponding to the instant in which the velovity becomes positive 
, when 
. We can find this time interval by using
And solving for we find
D) 5.6 rad
The angular displacement of the wheel is given by the equation
where we have
is the initial angular velocity of the wheel
is the final angular velocity
is the angular acceleration
Solving for 
,
When the spring is extended by 44.5 cm - 34.0 cm = 10.5 cm = 0.105 m, it exerts a restoring force with magnitude R such that the net force on the mass is
∑ F = R - mg = 0
where mg = weight of the mass = (7.00 kg) g = 68.6 N.
It follows that R = 68.6 N, and by Hooke's law, the spring constant is k such that
k (0.105 m) = 68.6 N ⇒ k = (68.6 N) / (0.105 m) ≈ 653 N/m
Answer:
Explanation:
Parameters given:
Mass of Puck 1, m = 1 kg
Mass of Puck 2, M = 1 kg
Initial velocity of Puck 1, u = 20 m/s
Initial velocity of Puck 2, U = 0 m/s
Final velocity of Puck 1, v = 5 m/s
Since we are told that momentum is conserved, we apply the principle of conservation of momentum:
Total initial momentum of the system = Total final momentum of the system
mu + MU = mv + MV
(1 * 20) + (1 * 0) = (1 * 5) + (1 * V)
20 = 5 + V
V = 20 - 5 = 15 m/s
Puck 2 moves with a velocity of 15 m/s
