If an object with a mass of #5 kg # changes speed from #4m/s# to # 7m/s#, by how much does its kinetic energy change?

2 Answers

Answer:

Change in KE#=82.5" "#joule

Explanation:

Given #v_f=7" "#m/sec and #v_0=4" "#m/sec
and mass #m=5" "#kg

Formula for Kinetic Energy :

#KE=1/2*mv^2#

Change in KE#=1/2*mv_f^2-1/2*mv_0^2#

Change in KE#=1/2*m*(v_f^2-v_0^2)#

Change in KE#=1/2*5*(7^2-4^2)#

Change in KE#=82.5" "#joule

God bless....I hope the explanation is useful.

Apr 30, 2016

Answer:

#=82.5J#

Explanation:

  • Mass of the object #m = 5kg#
  • Initial velocity #v_i=4m/s#
  • Initial velocity #v_f=7m/s#
  • The change in KE =#1/2xxm(v_f^2-v_i^2)=1/2xx5xx(7^2-4^2)J#

#=82.5J#