Answer:
rock will hit the ground at the same time.
Explanation:
given,
Jan throws rock vertically downward with some initial velocity(v).
Len throw rock at an angle of 30° with initial velocity(2 v) twice than the Jan
to find whose rock will hit the ground first.
it is given that rock is identical
now,
vertical component of velocity of the rock
= v₂ sin θ
= v₂ sin 30°
=
= v
hence the vertical velocity of the Len is same as that of Jan so the rock will hit the ground at the same time.
Let's think about the system that includes the spacecraft, the astronaut,
and all the equipment tied to him. In this system, nothing is moving relative
to anything else, so the total linear momentum is zero.
Now, suddenly, a blast of gas leaves the astronaut's little SCUBA tank, and
hisses away from him and the spacecraft, in that direction ===> .
The momentum of the cloud of nitrogen is
(mass) x (speed)
= (0.03 kg) x (900 m/s)
= 27 kg-m/s in that direction ===> .
Now is the perfect time to recall that momentum is conserved.
It can't be suddenly created or destroyed, it can't appear out of
nowhere, it can't disappear into nowhere, and the total amount
of momentum in a system is constant.
In order to keep the total momentum of this system constant, the
astronaut himself gets 27 kg-m/s of momentum in this direction <=== .
The mass of him and his equipment is 320 kg.
So ...
27 kg-m/s <== = (320 kg) x (speed <==)
Speed = 27 kg-m/s / 320 kg
= 0.084375 m/s in this direction <===
THe loss of 2 protons and 2 neutrons (also called a helium nucleus) is defined as alpha decay.
The general effort force equation for block and tackle to raise or pull a load can be expressed as
<span><span>S=<span>F/<span>μn</span></span></span>
</span>
where
<span>S
</span> is the effort force,
<span>F
</span> is the load force (often the weight of the object to be moved),
<span>μ
</span> is the mechanical efficiency of the system (1 in an ideal, massless, frictionless system of pulleys), and
<span>n
</span> is the number of ropes between the sets of pulleys.