You carry a 7.0 kg bag of groceries 1.2 m above the level floor at a constant ve

Question

You carry a 7.0 kg bag of groceries 1.2 m above the level floor at a constant velocity of 75 cm/s across a room that is 6.4 m long. How much work do you do on the bag in the process 439 J 373 J 82 J 0.0 J A 1.0-kg block and a 2.0-kg block are pressed together on a horizontal frictionless surface with a compressed very light spring between them. They are not attached to the spring. After they are released and have both moved free of the spring both blocks will have equal speeds. both blocks will both have the same amount of kinetic energy. the magnitude of the momentum of the heavier block will be greater than the magnitude of the momentum of the lighter block. the lighter block will have more kinetic energy than the heavier block. the heavier block will have more kinetic energy than the lighter block. ls it possible for a system to have negative potential energy Yes, as long as the total energy is positive. No, because the kinetic energy of a system must equal its potential energy. Yes, as long as the kinetic energy is positive. Yes, since the choice of the zero of potential energy is arbitrary. No, because this would have no physical meaning. An object attached to an ideal massless spring is pulled across a frictionless surface. If the spring constant is 45 N/m and the spring is stretched by 0.88 m when the object is accelerating at 0.9 m/s^2, what is the mass of the object 56 kg 44 kg 37 kg 48 kg In an INELASTIC collision between two objects both the momentum and the kinetic energy of the system are conserved. the momentum of each object is conserved. the kinetic energy of the system is conserved, but the momentum of the system is not conserved. the momentum of the system is conserved but the kinetic energy of the system is not conserved. the kinetic energy of each object is conserved.

Explanation / Answer

(6) ans

Given that

mass m=7 kg

hight h=1.2 m

constant velocity V=75 cm/s=0.75m/s

displacement s=6.4 m

this problem belong to work-energy power

according to work-energy therom

therfore the work done during this process

work done =1/2mV^2 + mgs

=1/2*7*(0.75)^2+7*(9.8)*6.4

=1.97+439.04

=441.01 J

so the correct option is 1

[7] ans

given that

mass m1=1 kg

mass m2=2 kg

this problem belongs to the linear and angular simple harmonic motion

according to oscillation of a two -particle system two - body system

initially the spring is compressed this exhibit newtons third law

as no external force is acting on the spring block system the displacement of centre of mass of system Xcm =0

therefore {m1+m2}Xcm =m1x1-m2x2

m1x1-m2x2=0

m1x1=m2x2

x1/x2=m2/m1=2/1

basing on this condition lighter block has more kinetic energy than heaiver block

so option is (d)

[8] ans

given that

negative potential energy means that the system is in the bound state an equal amount of positive energy is supplied to the system

so the potential energy is equal to positive kinetic energy

so the option (c) is correct

[9] ans

Given that

spring constant K=45 N/m

streaching of string X=0.88 m

acceleration A=0.9 m/s^2

this problem belongs to force law in oscillation

according to restoreing force ma=kx

   m(0.9)=45*0.88

therefore the mass of the system =44 kg

so the correct option (b)

[10] ans

given that

inelastic collision the momentum is conserved but kinetic energy is not conserved

so the correct option is (d)

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