Answer:
33.6 Ns backward.
Explanation:
Impulse: This can be defined as the product of force and time. The S.I unit of impulse is Ns.
From Newton's second law of motion,
Impulse = change in momentum
I = mΔv................................. Equation 1
Where I = impulse, m = mass of the skater, Δv = change in velocity = final velocity - initial velocity.
Given: m = 28 kg, t = 0.8 s, Δv = -1.2-0 = -1.2 m/s (Note: the initial velocity of the skater = 0 m/s)
Substituting into equation 1
I = 28(-1.2)
I = -33.6 Ns
Thus the impulse = 33.6 Ns backward.
Answer:
The magnitude of the average angular acceleration of the disk is 
.
Explanation:
Given that,
Angular velocity, 
The disk comes to rest, 
Time, t = 0.234 s
We need to find the magnitude of the average angular acceleration of the disk. It is given by change in angular velocity per unit time. So,
So, the magnitude of the average angular acceleration of the disk is .
Answer:
Water striders have strong intermolecular forces on their legs which enables them to run on water.
