If the bag is motionless, then it's not accelerating up or down.
That fact right there tells you that the net vertical force on it
is zero. So the sum of any upward forces on it is exactly equal
to the downward gravitational force ... the bag's "weight".
If the bag is suspended from a single rope, then the tension
in the rope must be equal to the 100-N weight of the bag.
And if there are four ropes holding it up, then the sum of
the four tensions is 100N. If the ropes have been carefully
adjusted to share the load equally, then the tension is 25N
in each rope.
Answer:
Mass of bike = 38 kg.
Explanation:
Kinetic energy is given by the expression, 
, where m is the mass and v is the velocity.
Here speed of child riding bike = 6 m/s
Mass of child = 30 kg
Total kinetic energy = 1224 J
Let the mass of bike be, m kg
So, total mass of child and bike = (m + 30) kg
Substituting,
So, mass of bike = 38 kg.
Answer:
6360 km
Explanation:
Use the kinematics equation 
. We are given t = 7.95 hours and a = 0 m/s^2 (constant speed means there is no acceleration). Solve for x.
Answer:
West
Explanation:
m = Mass of car = 
t = Time = 9 seconds
u = Initial velocity = 30 m/s
v = Final velocity = 0
Impulse is given by
The magnitude of the total impulse applied to the car to bring it to rest is .
The direction is towards west as the sign is negative.
For this problem, we use the derived equations for rectilinear motion at constant acceleration. The equations used for this problem are:
a = (v - v₀)/t
2ax = v² - v₀²
where
a is the acceleration
x is the distance
v is the final velocity
v₀ is the initial velocity
t is the time
The solution is as follows;
a = (60mph - 30 mph)/(3 s * 1 h/3600 s)
a = 36,000 mph²
2(36,000 mph²)(x) = 60² - 30²
Solving for x,
x = 0.0375 miles
