Answer:
4.4 seconds
Explanation:
Given:
a = -5.5 m/s²
v₀ = 0 m/s
y₀ = 53 m
y = 0 m
Find: t
y = y₀ + v₀ t + ½ at²
0 = 53 + 0 + ½ (-5.5) t²
0 = 53 − 2.75 t²
t = 4.39
Rounded to two significant figures, it takes 4.4 seconds for the object to land.
19-? Is the exact p.d across the 114-?resistor.
Current will different
But p.d will same in parallel circuit .
Answer:
and 
. The missing ion would be 
.
Explanation:
In a double replacement reaction, two ionic compounds exchange their ions to produce two different ionic compounds.
In this question, the two ionic compounds are:
, and
.
In particular,
- is made up of
ions and 
ions, while - is made up of
ions and ions.
In a binary ionic compound, cations (positive ions) can only bond to anions (negative ions.)
- is a cation. In , was bounded anions. During the reaction, it bonds with anions to produce .
- is also a cation. In , was bounded to ions. During the reaction, it bonds with anions to produce .
Hence, the two products will be and .
Note that charges on the ions must balance. For example, a ion carries twice as much charge as an ion. As a result, each ion would bond with twice as many ions as would in .
Answer
given,
mass of the drop, m = 0.0014 g
speed of the drop, u = 8.1 m/s
a) Change in momentum is equal to impulse
final velocity of the drop, v = 0 m/s
J = m ( v - u )
J = 0.0014 x 10⁻³ x ( 0 - 8.1 )
J = -1.134 x 10⁻⁵ kg.m/s
impulse of the roof = - J = 1.134 x 10⁻⁵ kg.m/s
b) time, t = 0.37 m s
impact of force = ?
we know
J = F x t
1.134 x 10⁻⁵ = F x 0.37 x 10⁻³
F = 0.031 N
the magnitude of the force of the impact is equal to F = 0.031 N
