Answer:
The mass of the ice block is equal to 70.15 kg
Explanation:
The data for this exercise are as follows:
F=90 N
insignificant friction force
x=13 m
t=4.5 s
m=?
applying the equation of rectilinear motion we have:
x = xo + vot + at^2/2
where xo = initial distance =0
vo=initial velocity = 0
a is the acceleration
therefore the equation is:
x = at^2/2
Clearing a:
a=2x/t^2=(2x13)/(4.5^2)=1.283 m/s^2
we use Newton's second law to calculate the mass of the ice block:
F=ma
m=F/a = 90/1.283=70.15 kg
Answer:
The speed of water must be expelled at 6.06 m/s
Explanation:
Neglecting any drag effects of the surrounding water we can assume the linear momentum in this case is conserves, that is, the total initial momentum of the octopus and the water kept in it cavity should be equal to the total final linear momentum. That's known as conservation of momentum, mathematically expressed as:
with Pi the total initial momentum and Pf the final total momentum. The total momentum is the sum of the momentums of the individual objects, in our case the octopus and the mass of water that will be expelled:
with Po the momentum of the octopus and Pw the momentum of expelled water. Linear momentum is defined as mass times velocity:
Note that initially the octopus has the water in its cavity and both are at rest before it sees the predator so 
:
We should find the final velocity of water if the final velocity of the octopus is 2.70 m/s, solving for 
:
The minus sign indicates the velocity of the water is opposite the velocity of the octopus.
Answer: the horizontal component of total momentum
Explanation:
Since the open cart is rolling to the left on the horizontal surface, the quantity that has the same value just before and just after the package lands in the cart is the horizontal component of total momentum.
Momentum, is the product of the mass of a particle and the velocity of the particle. The change of momentum depends on the force which acts on it. The addition of the the individual momenta is the total momentum.
Answer:
725.2 N
Explanation:
Since it is not stated the scale, the person or both accelerated or experience weightlessness, the net force acting on the bathroom scale is the weight of the person acting downward as the person stands on the scale .
Weight = mass of a body × acceleration due to gravity
= 74 kg × 9.8 m/s²
= 725.2 N
Answer: 
Explanation:
The de Broglie wavelength 
is given by the following formula:
(1)
Where:
is the Planck constant
is the momentum of the atom, which is given by:
(2)
Where:
is the mass of the electron
is the velocity of the electron
This means equation (2) can be written as:
(3)
Substituting (3) in (1):
(4)
Now, we only have to find :
>>> This is the de Broglie wavelength of the electron
