A car reaches 80 km/hr, then suddenly crashed into a concrete wall. Without a seat belt, the crash test dummy slams into the car's dashboard because
A the crash test dummy's kinetic energy drops to zero
B the dashboard is pushed backwards into the crash test dummy
C the crash test dummy continues its motion until acted upon by an unbalanced
force
D Gravity is pulling the crash test dummy in the direction the car is moving

Imagine that you push on a large rock. at what point does your effort change the rock’s mechanical energy?

Answer asap need it by wednesday morning carry out the following calculations on ph and ka of from data. i. calculate the ph of 0.02m hcl ii. calculate the ph of 0.036m naoh iii. calculate the ph of 0.36m ca(oh)2 iv. calculate the ph of 0.16m ch3cooh which has ka = 1.74 x 10-5 mol dm-3 v. calculate ka for weak acid ha which has a ph of 3.65 at 0.30m concentration vi. calculate the ka of a solution made by mixing 15.0 cm3 0.2m ha and 60.0 cm3 0.31m a-. [ph= 3.80] vii. calculate the ph of a solution made by mixing 15.0 cm3 0.1m naoh and 35.0 cm3 0.2m hcooh. [ka = 1.82 x 10-4 m]

Helium decays to form lithium. which equation correctly describes this decay?