Answer:
Explanation:
mass of refrigerator, m = 110 kg
coefficient of static friction, μs = 0.85
coefficient of kinetic friction, μk = 0.59
(a) the minimum force required to just start the motion in refrigerator
F = μs x mg
F = 0.85 x 110 x 9.8
F = 916.3 N
(b) The force required to move the refrigerator with constant speed
F' = μk x mg
F' = 0.59 x 110 x 9.8
F' = 636.02 N
(c) Let a be the acceleration.
Net force = Applied force - friction force
F net = 950 - 636.02
F net = 313.98 N
a = F net / mass
a = 313.98 / 110
a = 2.85 m/s²
Work = Force x Distance = 500 x 4 = 2000 Nm = 2000 J
Answer:
Explanation:
<u>Instant Velocity and Acceleration
</u>
Give the position of an object as a function of time y(x), the instant velocity can be obtained by

Where y'(x) is the first derivative of y respect to time x. The instant acceleration is given by

We are given the function for y

Note we have changed the last term to be quadratic, so the question has more sense.
The velocity is

And the acceleration is

Answer:
v = 2.18m/s
Explanation:
In order to calculate the speed of Betty and her dog you take into account the law of momentum conservation. The total momentum before Betty catches her dog must be equal to the total momentum after.
Then you have:
(1)
M: mass Betty = 40kg
m: mass of the dog = 15kg
v1o: initial speed of Betty = 3.0m/s
v2o: initial speed of the dog = 0 m/s
v: speed of both Betty and her dog = ?
You solve the equation (1) for v:

The speed fo both Betty and her dog is 2.18m/s