Answer:
Speed of both blocks after collision is 2 m/s
Explanation:
It is given that,
Mass of both blocks, m₁ = m₂ = 1 kg
Velocity of first block, u₁ = 3 m/s
Velocity of other block, u₂ = 1 m/s
Since, both blocks stick after collision. So, it is a case of inelastic collision. The momentum remains conserved while the kinetic energy energy gets reduced after the collision. Let v is the common velocity of both blocks. Using the conservation of momentum as :



v = 2 m/s
Hence, their speed after collision is 2 m/s.
As per the given Figure attached here we know that both charges q1 and q2 will apply same force on charge q3 and hence the resultant force due to both charges will be along Y axis vertically upwards
So here we know that

now from the above equation


so both of the charges will apply 0.288 N force on q3 charge along the line joining them
now the net force due to vector sum is given by

here we know that angle is

now we have


so net force on q3 is 0.46 N vertically upwards along +Y axis
Volume of a block can be found by: length × width × height. So:
3.5cm × 2.8cm × 1.6cm = 15.68cm^3
Answer:
copper will have more change in temperature as compare with aluminum
Explanation:
Hot piece of copper is made in contact with cold piece of aluminium
So here thermal energy transfer will take place from copper to aluminium
so by energy conservation we can say that heat given by copper is same as the heat absorbed by aluminium.
now we have

here we know that
= specific heat capacity of copper
= specific heat capacity of aluminum
given that specific heat capacity of aluminium is more than double that of copper
so we can say

so here if the mass of copper and aluminium is same then

so temperature change of copper is twice the temperature change of aluminium
So copper will have more change in temperature as compare with aluminum
That would be answer B
hope this helped you