Answer:
15.4 kg.
Explanation:
From the law of conservation of momentum,
Total momentum before collision = Total momentum after collision
mu+m'u' = V(m+m').................... Equation 1
Where m = mass of the first sphere, m' = mass of the second sphere, u = initial velocity of the first sphere, u' = initial velocity of the second sphere, V = common velocity of both sphere.
Given: m = 7.7 kg, u' = 0 m/s (at rest)
Let: u = x m/s, and V = 1/3x m/s
Substitute into equation 1
7.7(x)+m'(0) = 1/3x(7.7+m')
7.7x = 1/3x(7.7+m')
7.7 = 1/3(7.7+m')
23.1 = 7.7+m'
m' = 23.1-7.7
m' = 15.4 kg.
Hence the mass of the second sphere = 15.4 kg
Answer: 2.04 s
Explanation:
Let the initial velocity be v, Angle of projectile be
Then the horizontal component = v cos θ = 16 m/s
Vertical component of velocity = v sin θ = 20 m/s
Time taken to reach the highest point is half the time taken for total flight.
Time for total flight,


Thus, the football takes 2.04 s to rise to the highest point of its trajectory.
It would be the first option.
Explanation-
The number of protons is equal to the atomic number the number of neutrons is the mass minus the atomic number.
Answer:
the current flowing in each is the same.
Explanation:
When resistors are connected in series, they are connected in the same branch of the circuit - this means that the same current flows through each resistor.
The other options listed are wrong because:
the same power is dissipated in each one --> false: the power dissipated in each resistor is
, where I is the current and R the resistance, so it depends on the value of the resistance
the potential difference across each is the same.-- > false: this is true in parallel circuits, not series circuits
the equivalent resistance of the circuit is less than that of the smallest resistor.--> false: the equivalent resistance of a series circuit is the sum of the individual resistances:
, so it is larger than the resistance of the smallest resistance
the equivalent resistance of the circuit is equal to the average of all the resistances. --> false: the equivalent resistance of a series circuit is the sum of the individual resistances:
, not the average
The answer is D
The body of water contains more molecules; more molecules, more kinetic energy, which creates thermal energy.
The molecules are moving faster is the coffee, so the temperature is higher.