Answer: k = 5.4kg/m
where m is the mass of the crate.
Explanation:
The force of kinetic friction is described by the equation:
Ff = k*N
in the opposite direction in wich the object moves, where k is the coefficient of kinetic friction and N is the normal force, that is equal to the weight of the crate. N = m*g where m is the mass of the crate and g is the gravitational acceleration.
If the crate keeps moving with constant velocity, this means that the crate is not accelerating so there is no net force applied on the crate. Then the friction force should be equal in magnitude to the horizontal force of 53N (but with different sign)
then we have:
k*m*g = 53N
k*m = 53N/9.8m/s^2 = 5.4kg
k = 5.4kg/m
In the question we do not have the mass of the crate, so you must put the value in that equation to get the value of k.
Answer:
The velocity of the boy and the bicycle is 2.2 m/s.
Explanation:
We have,
Mass of child is 30 kg and the mass of bicycle is 20 kg. The combined momentum of the child and the bicycle is 110 kg-m/s.
It is required to find the velocity of the boy and the bicycle. The momentum of an object is given in terms of mass and its velocity. So,

M is combined mass of child and bicycle

So, the velocity of the boy and the bicycle is 2.2 m/s.
<span>Every effect. Velocity is d/t distancee over time. Increase t velocity (Speed) decreases. Increase d velocity increases.</span>
It depends, What is the balloon filled with? Just air, heilum, water, etc. If its just air then the bowling ball would most likly hit first, but if the balloon is filled with water it would problably hit at the same time, theres also air resistace to think about is there any or it is almost like a vaccum chamber?
Answer:
t = 180 / 1.4 = 129 sec (time to swim horizontally across river)
S = 129 sec * V where V is speed of current and S is the distance he will be carried downstream
The problem does not specify V the speed of the river