Answer:
so initial speed of the rock is 30.32 m/s
correct answer is b. 30.3 m/s
Explanation:
given data
h = 15.0m
v = 25m/s
weight of the rock m = 3.00N
solution
we use here work-energy theorem that is express as here
work = change in the kinetic energy ..............................1
so it can be written as
work = force × distance ...................2
and
KE is express as
K.E = 0.5 × m × v²
and it can be written as
F × d = 0.5 × m × (vf)² - (vi)² ......................3
here
m is mass and vi and vf is initial and final velocity
F = mg = m (-9.8) , d = 15 m and v{f} = 25 m/s
so put value in equation 3 we get
m (-9.8) × 15 = 0.5 × m × (25)² - (vi)²
solve it we get
(vi)² = 919
vi = 30.32 m/s
so initial speed of the rock is 30.32 m/s
Answer:
Explanation:
Net electric field at the centre will be zero .
Since all the charges are equal and they all are symmetrically situated around the centre . So the electric field produced by each will cancel out each other and hence the resultant electric field will be zero . It happens because electric field is a vector quantity and therefore it adds up vectorially . All the four electric field will form two pairs , in each pair electric fields are acting in opposite direction . So they all cancel out to zero .
The second one is best. Gravity is an attractive force that acts between all objects, whether they're in contact or not.
I believe you mean Tim Peake ? .Major Timothy Nigel "Tim" Peake CMG is a British Army Air Corps officer, European Space Agency astronaut and International Space Station crew member.
Born: April 7, 1972 (age 44), Chichester, United Kingdom
Space missions: Expedition 46, Expedition 47, Soyuz TMA-19M
Nationality: British
"An object weighs about two times as much on Jupiter as on Neptune." Hope this helps :)
